Comments 1 to 31:

1. RSVP at 16:01 PM on 3 May, 2010
   It was snowing in Barcelona, Venice and Mallorca a few months ago. How common is this?
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2. RSVP at 16:03 PM on 3 May, 2010
   ...before the Iceland volcano eruption.
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3. Jeff Freymueller at 16:09 PM on 3 May, 2010
   Very nice detective work! Your last paragraph is well stated. If rain in April starts to be commonplace in these places, that would be empirical evidence for climate change. A single bizarre event, by itself, can be consistent with what is expected from climate change. But you can never be certain that a single bizarre event is really due to climate change, even if climate change makes it more probable.
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4. CoalGeologist at 16:16 PM on 3 May, 2010
   Several weeks ago, I was enticed into an email "debate" with a AGW "skeptic" who argued that because February, 2010 was the first February on record when there were no tornadoes in the United States, this demonstrated (somehow?) that AGW wasn’t happening. I can’t say I understood his reasoning (if there was any!), but the question raised the issue of the distinction between "weather" and "climate". In this regard, it's best to conform to standard definitions, as appear below in my (overly-long!) post. As shown in the reply by RSVP @#2, using statistically rare "extreme weather events", or even more protracted "extreme climate events" to draw inferences regarding climate change is fertile ground for "cherry picking", and for this reason is best avoided. It is a "double edged sword" to use single events as providing proof that AGW is occurring, when certain other rare "events" such as this past cold, snowy winter in the eastern U.S. could potentially be cited as proof that AGW is a "hoax". Ultimately, climate is a statistical phenomenon. In this regard, single events can be measured in terms of their statistical likelihood, as has been done here. They do not, however, in and of themselves, describe climate, nor climate change, no matter how "bizarre" they may be. The recent flap over whether there has been statistically significant warming in the U.K. since 1995 demonstrates that even multi-year trends can be used to prop up invalid conclusions, if one approaches the topic of climate change with a biased agenda. For reference, the following definitions are from the Glossary section of the IPCC 2007 AR4 Report: "Climate": Climate in a narrow sense is usually defined as the average weather, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period for averaging these variables is 30 years, as defined by the World Meteorological Organization. The relevant quantities are most often surface variables such as temperature, precipitation and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. In various chapters in this report different averaging periods, such as a period of 20 years, are also used. "Extreme Weather Event" AND "Extreme Climate Event": An extreme weather event is an event that is rare at a particular place and time of year. Definitions of rare vary, but an extreme weather event would normally be as rare as or rarer than the 10th or 90th percentile of the observed probability density function. By definition, the characteristics of what is called extreme weather may vary from place to place in an absolute sense. Single extreme events cannot be simply and directly attributed to anthropogenic climate change, as there is always a finite chance the event in question might have occurred naturally. When a pattern of extreme weather persists for some time, such as a season, it may be classed as an extreme climate event, especially if it yields an average or total that is itself extreme (e.g., drought or heavy rainfall over a season). "Climate change" Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer... [the definition continues, but the latter parts are not relevant here.]
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5. SoundOff at 16:24 PM on 3 May, 2010
   Most parts of Canada had an exceptionally mild winter earlier this year. Witness the winter Oympics near washout in Vancouver. It was 25°C on April 2 in my area (Toronto) – the normal is 8°C for that date. That blew away the previous record of 20.6°C in 1967. Incidentally, I wore my winter coat only two days this past winter, unlike every day the previous winter. This anomalous weather must be credited to the recent El Niño, since global warming stopped a while ago according to skeptics.
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6. HumanityRules at 19:08 PM on 3 May, 2010
   If you want bizarre weather come to Melbourne. One summer day we had temperatures over 30oC followed by an evening hailstorm! How is the rain recorded? What was the temperature on the day?
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7. HumanityRules at 19:36 PM on 3 May, 2010
   So normal April temps at Resolute and Eureka are -20oC. Apr 24th and 25th 2010 temperature was around -10oC (as high as -6oc). Seems rain wasn't the only strange weather that weekend.
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8. wanderers2 at 19:40 PM on 3 May, 2010
   I was fortunate, as a 19-year-old, to get a job in the Canadian High Arctic (as an assistant carpenter/plumbers/electrician's helper). Yes that meant I visited places like Eureka, Resolute, Mould Bay, and Alert (Weather Station Isaachsen had already been closed by that time). Sighting narwhals from the air (thank you De Havilland Canada for building the incomparable twin otter) was fun. Encountering a polar bear on the ground (me carrying no gun and hiking alone and therefore illustrating the stupidity of my youth) was not. But seeing thousands of nesting murres, or the occasional snowy owl or snow bunting. That experience drove me towards a lifelong pursuit of ecology. Recently I have returned to the arctic, where I consistently see, and hear, from aboriginal persons, hunters, ornithologists, and others: that trends are all congruent with what is expected or projected by climate models. John, you do a great service with this website, and the best part of it is to provide access to the primary literature that others might have a hard time finding. If I had one request it would be to further synthesize some of the recent phenological papers. Thank you.
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9. JMurphy at 20:13 PM on 3 May, 2010
   RSVP, your Spanish examples are no doubt uncommon but hardly bizarre, I believe. Barcelona's 'maximum number of snow days in a month' (4) occurred in Feb 1938. Mallorca's maximum, (3) occurred in Jan 1985. The overall picture for the last Spanish Winter doesn't suggest any particularly bizarre events. In fact, the only unusual snow events occurred in A Coruña (Airport), Santander, Madrid (aerodrome of Cuatro Vientos), Toledo, Valencia (Manises airport) and Seville (Airport), where the number of days of precipitation in the form of snow surpassed the previous maximum values for January. On checking those stations, though, you will notice that accurate readings only began in, respectively, 1971, 1945, 1982, 1966 and 1951. (I haven't included Santander because although readings began back in the 20s, it is still showing 1956 as the heaviest year). Since most other places I have checked show a maximum snowfall around the 1930s or 50s, it can be perhaps claimed that the above stations may well have been higher then also, if only accurate readings had been taken at the time. You can check them all here. Uncommon weather indeed but not bizarre, surely ?
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10. Berényi Péter at 20:36 PM on 3 May, 2010
    There is a METAR record for Clyde, Nunavut, 1973 April 18, 20:00 AST (70.48 N, 68.52 W) indicating some rain. Same for Pond Inlet, Nunavut (72.70 N, 77.97 W) on 1985 April 25 01:00 EST and several more on 1995 April 27 Unfortunately Isachsen, Nunavut (78.78 N, 103.53 W) has only reported on 15 & 16 April 2010, so the anecdotic claim about April's rain on 24/25 is not supported by hard evidence. There was some rain there indeed on 1975 June 7 as claimed by the article. However, it could not be the earliest recorded rainfall on that spot, for there was also some rain there three days erlier. And of course there was no rain at all in May, 1988 at Alert, Nunavut (82.50 N, 62.33 W). On the other hand, there was some rain there last year on April 3 (maximum temperature for the day is -32 °C!). That much about reliability of press releases.
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11. HumanityRules at 21:17 PM on 3 May, 2010
    Ron, Just to prove I can do something as boring as you in the name of enlightenment I decided to have a look at some of those high Canadian records. I choose Eureka because from the map it looked like the closest to the site of this rain. The max temp in Apr 2010 was -4.7oC (-5.2oC on the weekend in question). So I checked for some other 'high' temps in Apr at Eureka. Here's a few of the balmiest Apr days (year, day in Apr, temp oC) 2010 23rd -4.7 1948 28th -5.0 1951 30th -6.1 1953 25th -3.3 1961 19th -6.7 1971 26th -2.8 1975 28th -5.0 1979 12th -3.1 (these are not all of them, just the warmest in a particular year and I reached my boredom threshold in the mid 80's) While unusual it looks like the temps in 2010 aren't unique. It's a shame the records don't go back further because my understanding is that the 1930's and 1940's were a period of warmer arctic temperatures. Going through the record I noticed all forms of precipitation are rare in Eureka in Apr (average for whole of Apr is 3.5mm). Apr 2010 had 15mm of precipitation. Hope this helps to stop people going off the deep end :)
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12. Mythago at 21:34 PM on 3 May, 2010
    I won't profess to having had time to go through reams and reams of data but to my mind it is possible for all unique or rare or even bizarre events as being nothing more than pure fluke chances of something having happened. Micro-climates exist all over the place. Here in North Oxfordshire we got a massive winter snowfall compared with the last 15 years that I can recall. Is that bizarre? Is that proof that AGW is not happening or is happening? I firmly believe that we have influenced the natural cycles of climate change, which would normally take millennia to occur, by pumping out massive amounts of all manner of polluting gases (AGW gases) and it is obvious that the climate is warming from very basic evidence but I really despair when one-off events are even hinted at as evidence to prove or disprove what is a very obvious trend which is already being proven and is based on global scale, long term evidence. I reckon someone was fishing by putting out the bait and you were conscientious enough to want to genuinely want to answer in as honest a way as possible. However beware the origin of this item. They may seem all interested and curious on the outside but on the inside they are possibly looking for a fight. I bet they try to use some of your article to suggest something alternative and argumentative later on elsewhere. The sceptics are getting desperate for an argument that they can say disproves AGW and will dig as deep as is possible and use whatever tactic is readily available. As the old saying tells us, 'There are lies, damn lies and statistics'. The lists you quote are incontrovertible evidence but they prove nothing unless you try to say they do with some argument, no-matter how well founded, that shows reasonable proof of a pattern or trend. That's when the sceptics strike with counter evidence. Its all a silly game and as far as I am concerned its a waste of time. Lets just put down the charts and tables and get on with abandoning fossil fuels and start being realistic about the planets ability to sustain us as a species. AGW! Its happening. We need to prepare for the worst case scenario and no amount of tables and charts and nit-picking over micro details will stop it happening. Have a nice day. Kev C.
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13. Dennis at 22:39 PM on 3 May, 2010
    Re: CoalGeologist #4 wrote "It is a 'double edged sword' to use single events as providing proof that AGW is occurring, when certain other rare "events" such as this past cold, snowy winter in the eastern U.S. could potentially be cited as proof that AGW is a 'hoax'." The Eastern U.S. this past winter may indeed be categorized as "snowy," but -- depending on how you categorize "Eastern U.S.," it is debatable to call it "cold" (or, more accuirately, "colder"). While Washington, D.C., had record snowfall totals from December through February, March recorded the forst time since record keeping began that the temperature did not drop below freezing (even overnight). I leave up to the scientists if increased precipitation is linked to a warming world. However, ceteris paribus, higher temperatures are. So, I agree with coal geologists, and have found that the AGW-is-a-hoax crowd have ignored the temperature record int he evidence.
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14. CO2 at 23:47 PM on 3 May, 2010
    HumanityRules #7 Hail is formed in severe thunderstorms reaching great hight. The surface temperature has no more to do with this than creating the conditions that formed the thunderstorm to begin with, which may be 20,30 or 40 degrees C. Are we talking climate change?
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15. Rob Honeycutt at 01:13 AM on 4 May, 2010
    I have to agree with CO2 (#14). Hail is formed by rising moisture in thunderheads that can sometimes reach over 50,000 feet high. Such storms only form in the presence of warm moist unstable air (summer). One would expect it to be warm at the surface when getting hail.
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16. Ron Crouch at 02:15 AM on 4 May, 2010
    #10 Berényi Péter While the Metar report you supplied for Clyde River Apr 18, 1973 clearly states rain it also shows no accumulation. In contrast the Environment Canada Daily and the Environment Canada Hourly records indicate no precipitation at all. Now the Metar report you supplied for Pond Inlet for Apr 25, 1985 clearly states "fog,rain,snow" with an accumulation of .1 cm. The Environment Canada Daily and the Environment Canada Hourly records clearly indicate snow on that date with total precipitation registering .6 mm. Moving on to Isachsen on June 7, 1975 The Metar report indicates fog with no accumulation of precipitation. On June 4, 1975 the Metar report does indicate "rain,snow" with no accumulation. So let's see what Environment Canada has to say about those dates on a daily basis. Well June 7 shows rain accumulation of .3 mm and June 4 shows the same with a trace of snow. So moving on to the hourly report for June 7 it indicates drizzle and fog throughout the day. Now on June 4 the hourly report indicates rain and snow changing to rain late in the evening. So yes the claim that June 7, 1975 being the first recorded rainfall at Isachsen is incorrect as it clearly took place three days earlier on June 4. So we'll have to give David Phillips at least an "E" for effort on that one. Now for the final item which is May 1988 in Alert. The Metar record supplied shows a total of 4 cm precipitation for the month and shows no precipitation on the 21st and .1 cm on the 22nd. So what do the Environment Canada records say. Well it shows a .2 mm accumulation of rain on May 21 followed by a trace of rain on May 22. So in conclusion, seeing that we are dealing with Canadian Climate Records then it is only appropriate when doing an analysis that we use the official Canadian documents from Environment Canada. Other than the small blurb that David had over June 7, 1975 for Isachsen, I'd say the climate record contentions are fairly spot on.
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17. Ron Crouch at 02:34 AM on 4 May, 2010
    My apologies the link to the daily data for Isachsen for June 1975 should point here.
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18. Geo Guy at 03:13 AM on 4 May, 2010
    Interesting post and just goes to show that climate doesn't always fall into neat organized categories. In 1973 I was working in Uranium City in northern Saskatchewan (north shore of Lake Athabasca). At 8:00 pm on New Year's eve (73-74)it was -40 F (we hadn't switched to metric then). When we left the festivities at about 12:45 am New Year's day, the temperature had sored to +40F! By 10:00 am later that morning it had dropped to about - 10F. I am sure there are many other oddities in the weather, especially in areas that are isolated as in Northern Canada, that go unreported. Certainly rain in April is not that far fetched - it may have happened 20 km away from the weather station in the past but simply went unreported. Having worked in isolated areas of Canada in the past I can assure you that things such as thunder showers in winter happen, although not that frequently. Calgary (where I currently live) has had significant snow falls in August and golf weather in January, all which seem to be linked to where the jet stream is located. I guess what this can tell us is climate and climate change is a multi-faceted process contingent not upon one single parameter but rather it is the result of the interaction of many parameters.
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19. Ron Crouch at 03:24 AM on 4 May, 2010
    I had hoped to do this all in one post but there were some technical difficulties with the Environment Canada website. #10 Berényi Péter Your last point surrounding the Metar report for Alert on Apr 3, 2009. Although the Metar report clearly states rain with no accumulation it is unsupported by either hourly reports from Alert airport which only reports ice crystals, or Alert Autonomous which shows a trace of snow.
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20. Phila at 04:08 AM on 4 May, 2010
    #4 CoalGeologist "It is a "double edged sword" to use single events as providing proof that AGW is occurring, when certain other rare "events" such as this past cold, snowy winter in the eastern U.S. could potentially be cited as proof that AGW is a "hoax"." Without condoning citing single events as "proof" of AGW, I think the difference is that cold, snowy winters are consistent with AGW. While it may be an error to make too much of, say, a heat wave, it's an error of an entirely different type to claim that if it gets cold in the Northern Hemisphere in winter, then AGW must be a hoax. One results from confusion; the other is an attempt to produce it.
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21. Philippe Chantreau at 05:06 AM on 4 May, 2010
    I've dealt with METARs a lot during my days as a pilot and flight instructor. They are automated reports from stations that rely on sensors. Pilots learn to not rely too extensively on reports from unmanned stations, especially for some indications. The station "looks" at a rather small extent of sky, so sky cover may be different from reality. Visibility is ground visibility (normally measured in a direction parallel to the runway axis from the station location) and may not be the same as the slant range visibility that matters when looking for the runway treshold in an instrument approach. Some stations have a precipitation discriminator (type2 if I recall, it usually figures in the remark section of the aviation METAR), others don't. Even the ones that have it can experience temporary malfunctions of the sensor. Some types of precipitation are more likely to "confuse" the sensors, like heavy fog that falls as very fine drizzle (especially below freezing), or freezing rain. The stations are a great tool, but they're only robots and ill-equipped to give an accurate rendition of what goes on in complex weather situations. You could have a cold layer near the ground just a couple of hundred feet thick, with layers of various and higher temperatures as altitude increases, leading to all sorts of variations in precipitation. What was described by Geo-Guy certainly reflects one of these types of situations evolving over time, seen from the ground. It's all weather. I would not put too much trust in such minute amounts of precip as were reported in the METARs linked by John and other posters.
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22. Pete Dunkelberg at 09:43 AM on 4 May, 2010
    # 5 Soundoff "This anomalous weather must be credited to the recent El Niño, ...." Think Arctic Oscillation.
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23. SoundOff at 14:15 PM on 4 May, 2010
    Arctic Oscillation, when very negative, as it was this past mid winter, produces extreme cold spells east of the Rockies, over Europe and eastern Asia. That’s exactly what we saw in January & February. The mild winter in most of Canada would be better explained by the the recent El Niño. NSIDC - Effects of the Negative Phase of the Arctic Oscillation
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24. Pete Dunkelberg at 04:42 AM on 5 May, 2010
    That 1 or 2 degree warmer area in the tropical Pacific has a long reach! Or, from your link "This [the positive phase of the AO] keeps much of the United States east of the Rocky Mountains warmer than normal, but leaves Greenland and Newfoundland colder than usual. Weather patterns in the negative phase are in general "opposite" to those of the positive phase, as illustrated below." When the wind blows hard from the Arctic, the Arctic does not become a giant vacuum. Other, warmer air blows in from elsewhere. The slightly warmer air from the tropical Pacific, even if it gets there without cooling much, could not account for the very high arctic temperatures. What does it is the quantity of air from lower latitudes, which must match the quantity of air blowing out of the Arctic. I had hoped that mentioning the AO would make a light bulb go off. How does it correlate with warm Arctic years in the past?
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25. actually thoughtful at 11:08 AM on 5 May, 2010
    #24 - can you make your point differently? Are you saying warming arctic corresponds with negative AO? The opposite? Something different? A quick review shows that AO is not strongly correlated with temperature in 1999 and 2005 (notably hot years...).
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26. SoundOff at 14:13 PM on 5 May, 2010
    #24 - Pete, It’s a regular pattern, at least in east central Canada. Each El Niño episode does give us very mild winters. And colder winters result when a La Niña episode is in effect (such as the prior two winters before this last one). So yes ENSO does have a long reach. Keep in mind that Toronto is slightly closer to the equator than to the North Pole, at the same latitude as southern France (but without the palm trees), so we get influenced by both ends. Perhaps in the far north, the Arctic Oscillation normally dominates. I did notice that Canadian Arctic surface temperatures were significantly above normal, while at the same time the Canadian prairies and US plains states were freezing under the deepest part of the negative AO. There’s much supporting science that says the stratosphere above the Arctic warms during the negative phase of an AO but little science making such claims for surface temperatures. So I’m not prepared to say that a negative AO typically results in warmer Arctic surface temperatures. Analyzing it logically, if the air pressure is high in the north and low in the mid latitudes (a negative AO), then what one should see is the surface air moving generally from north to south (from the high pressure area to the low pressure area). This in turn should pull down some upper atmosphere in the north to replace the exiting air, which in turn, pushes the higher level jet stream to move in the opposition direction to fill the high level void created in the north, and lifting air out of the south to complete the circle. These movements would all have a slight eastward slant due to planetary rotation. With colder high level air being pulled down in the north, one would expect things to be a bit cooler up north on the surface, and some minor ice extent recovery this past winter is evidence that this did happen overall. But how does one explain the warm surface temperatures I noticed in the north at the peak of the negative AO? I don’t know but perhaps, with an El Niño raging on top of the usual GW and a negative AO, just maybe a layer of warm Pacific air was being pulled in below the north and east moving jet stream during that same time and it was filling the surface viod in the far north instead of higher air. Weather is very chaotic so it’s hard to say. The early rainfalls reported in this article were well after the negative AO peak (but still within the ENSO influence), so we might have moved off topic by discussing AO here, but it was worth considering nonetheless.
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27. Westwell at 21:54 PM on 5 May, 2010
    Climate change? Global warming? Maybe it's just the weather, did anyone think of that? Lots of Ice—But No Media Coverage http://www.hawaiireporter.com/story.aspx?0b9e4b5f-5225-40c7-b775-03c822fbffc8 Catastrophic” retreat of glaciers in Spitsbergen http://wattsupwiththat.com/2010/05/02/catastrophic-retreat-of-glaciers-in-spitsbergen/
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28. michael sweet at 22:23 PM on 5 May, 2010
    Westwell: Perhaps your reporter in the Hawaii story should have reported on ice in the great lakes last year, since they used data from last year. There was a lot of ice in the great lakes last year. It was a La Nina year. This year, in contrast, was record lows. Last year was high for recent years, but not record highs. It is easy to cherry pick data to try to influence people who are uninformed. You will have a lot more trouble on this site where people check what you say.
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29. mspelto at 00:31 AM on 6 May, 2010
    Sometimes an event such as the rain even here is spatially or temporally limited and of as such is an isolated weather event. If it coincides with other events spatially and temporally then it is just another measure of a broader event that is important. For example February had the 3rd highest mean snowcover extent of the last 44 years in North America according to the Rutgers Global Snow lab. The most extensive melt off of snowcover in the last 44 years has occurred in March and April. Leading to March mean snowcover extent being the 18th of 44 years, and April being the 41st highest of 44 years. That is correct going from third most to third least snowcover. This indicates a continent wide period of unusual melt conditions.
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30. Philippe Chantreau at 03:29 AM on 6 May, 2010
    Interesting facts Mauri. I won't hold my breath to see it reported on the "skeptic" web sites where the record February snow cover was trumpeted as some sort of proof of something or other...
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31. RSVP at 17:53 PM on 6 May, 2010
    Perhaps that could be a new skeptical argument... "too much data", or "too much new data".
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