Here's the situation: Anaktuvuk is at 68.1N 2100' in the Brooks Range; the village is right on the valley floor and within one mile of the continental divide. On general principles, it seems to me that it is (barely) within the realm of possibility that IF there was a fresh snow cover and IF an unseasonably cold airmass in place AND skies cleared late evening AND winds were light that Anaktuvuk could get this cold in late June (this would be a lot more believable if it was the first few days of June).
There are historically very few weather observations from this part of the world, and the data quality from the coop observation at Anaktuvuk during this time have more than a few problems. Here is the scan of the original form for June 1967:
|Courtesy of NCDC|
If these are really observations taken at 5pm (and differences from the scheduled time of observation are hardly ever recorded by the observer on the form), the data on the 24th looks suspect: was it really 40F at 5pm on the 23rd, fell to 17F the following morning ( itself a remarkably low temperature for so late in June), then rebounded to 60F, only to be back to 35F by 5pm on the 24th? The high temperature of 44F on the 25th looks plausible. Notice too the remark concerning snow cover on the morning of the 27th, but nothing that would suggest snow on the ground on the morning of the 25th.
If we look at what was happening on the broader scale, here's the NCEP/NCARR Mean Sea-Level Pressure and 850mb temperature reanalysis for Jun 25, 1967:
|Courtesy of NCEP/NCAR|
It would be nice to have some explanation of how the -1F got to recorded, but I can't think of any offhand. So, lacking any additional evidence, my vote is: beyond reasonable doubt, the low temperature was not -1F at Anaktuvuk Pass on June 25, 1967. However, there IS a very slight chance that the all the ingredients came together and that the observation of -1F is correct.
Well, there was a 2F recorded on the 9th, so why not colder later? Assuming Deg F and C weren't transposed.ReplyDelete
My camping/working in the Brooks Range, and Denali Highway during summer has led me to believe cold is possible. Valley floors tend to collect cold air that descends from nearby mountains during periods of sunlight shading and calm condx with little air mixing. Anaktuvuk is surrounded by such cool air generators.
With cold air above (850mb), the passage of cold northerly flow, or radiational cooling, it may have been colder than normal.
Who knows...was it real or was it Memorex?
Thanks for the comments and insights. I figured you would have some good thoughts on this! The data as it stands certainly looks suspicious, with some wild variations in the minimum temperatures that summer. We have the somewhat implausible low of 2F on the 9th, then the -1F in question, then lows of 8 and 12 F on July 20 and 21.
Following your lead, I pulled up the original forms from the surrounding months and found some very interesting comments on the minimum temperatures. Most intriguingly, the comment on Jul 28 appears to state "Min was 45 below I did not put it on thought it is not right". There are also comments on several other dates about not recording the minimum temperature, but these are difficult to read/interpret: something about the minimum marker and the "ball" (July 5 and 6, August 30, September 1), then on September 10 "Minimum needle is in the ball again". It seems clear that there was some technical problem with the thermometer - perhaps it will make sense to you.
Also, for what it's worth, the observer seems pretty consistent about noting snow conditions, so it may be safe to assume there was not a fresh snow cover on June 25 - which makes the record low even less likely to be correct.
Thanks for the forensic work Richard. Excellent procedure to look at additional months. So we have 4 days in the June & July of 1967 colder in the respective months than any in Alaska ever at low elevation. Not credible.
The remarks about the "needle in the ball" sure sounds like it refers the min temp thermometer and the index. This is problem that I think I've seen before.
Thanks... the question has intrigued me for a long time, so it's satisfying to finally get some additional information on it. Do you know if there is a procedure for having a record like this officially flagged as suspect or incorrect? It would be nice to have the June state (and national?) minimum temperature record updated at NCDC.
Of course the next question will be, what IS the lowest credible temperature recorded in Alaska in June and/or in the summer months? Time to start investigating...
email me about the Anaktuvuk temperature issue.
Always glad I read your blog, Rick. Very interesting.ReplyDelete
I don't believe this is correct. 90% is wrong. There are NO OTHERS BELOW 0F in Anaktuvuk Pass in June, not even in the begin of the month. I have scanned the metadata (not all years are available) and the latest below 0F I found are around May 20-25th. Note that -1F would be the coldest temperature ever recorded in June in any inhabited place in the WHOLE HEMISPHERE and it would be lower than any temperature ever recorded in the whole hemisphere at low and mid-low elevation .0F or -17.8C is the record of Cambridge Bay ,Canda, and Cape Chelyskin,Russia, the June lowest in the Hemisphere except for high elevations of course (Greenland ice cap, Alps, Mt Mc Kinley, Mt Logan, Himalaya....). The fact it would have been recorded at the end of the month would make it an absolute anomaly in terms of WORLD climatic statistics. Weird. Weather maps and temperatures in nearby stations DO NOT SUPPORT the credibility of that reading. 10% correct 90% incorrect in my opinion.Maximiliano Herrera,climatologist.ReplyDelete