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The book Minus 148 Degrees is written about a winter climb of Denali in which a rapid weather change forced the climbers to seek refuge in an emergency snow cave.

The title is a reference to the claim that the wind-chill temperature was negative 148 degrees F.

What was the actual temperature (as opposed to the wind-chill temperature) during this event?

I do not own a copy of the book and cannot find the answer to this, but I assume someone somewhere must know. If we at least have wind estimates we could work backward to estimate the temperature.

I did find an interview with the author of the book in which the interviewer mentions something about negative 40 degrees, but the author neither confirms nor denies this, and it could well be a typo in which 140 was intended, which might be likely as -148 degree wind chill from -40 degrees appears to require nearly hurricane wind speed.

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Loduwijk
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  • Hurricane speed winds are pretty common high up on Denali. – Charles E. Grant Jun 27 '18 at 23:04
  • @CharlesE.Grant Interesting. So, to give this Q&A a push in the right direction, I'll suggest that maybe the -40 actually is the correct answer. Would you concur? I hesitate to put it as an answer though, as it was merely 1 number mentioned in passing by a reporter. – Loduwijk Jun 27 '18 at 23:52
  • The Japan Alpine Club placed a weather station near the summit of Denali in 1990. The lowest temperature it has recorded is -75°F. The lowest windchill it has recorded is −118.1 °F. Clearly it could have been much colder than -40, so this doesn't provide a conclusive answer to your question. Of course in terms of human function and survival the wind chill is really the relevant factor. The temperature would be more relevant for the mechanical properties of materials. – Charles E. Grant Jun 28 '18 at 00:33
  • The concept of windchill breaks down at those temperatures. To claim "the windchill temperature reached -148°C" is simply incorrect, for windchill is not defined there. – gerrit Jun 28 '18 at 09:22
  • @gerrit The claim was minus 148 F. At what wc does the concept break down? – ab2 Jun 28 '18 at 09:51
  • @ab2 Although personally I don't like wind chill at any temperature, this is the best source I could find right now. Wind chill is calculated at a height of 1.5 m for exposed skin for a person walking at 1.34 m/s. Test subjects were exposed to winds up to 8 m/s at temperatures down to -10°C (I guess colder would be dangerous). Below that it's extrapolated. With successive models, the windchill estimate at -1°C with 40 km/h wind has increased from -40°C to -18°C to -9°C, which to me just shows how uncertain the whole concept is. – gerrit Jun 28 '18 at 10:08
  • Although the BAMS paper claims that Unlike the old wind chill, there is no minimum wind speed below which WCT cannot be calculated, as even in zero wind there is a relative air movement equal to the walking speed, personally I seriously question the validity to severely extrapolate this largely empirical model. Also note that an uncertainty analysis is completely lacking. And the book is apparently using an older version which may be even more inaccurate. – gerrit Jun 28 '18 at 10:13
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    @gerrit This is valuable information, and, although it does not answer the OPs question, I think it should be an answer or incorporated into an answer. – ab2 Jun 28 '18 at 12:16
  • Related https://outdoors.stackexchange.com/questions/19808/how-much-difference-does-the-wind-chill-matter-if-you-are-inside-a-snow-cave – Charlie Brumbaugh Jun 28 '18 at 13:41
  • @CharlesE.Grant Since the people survived in a snow cave, I was assuming that the wind chill was much less a concern for them, as they were not directly (possibly not at all; I haven't read the book yet) exposed to the wind. So it is really cool that it may have been such awful conditions, but in their cave, if done properly (I assume it was, hence their survival), then it was likely warmer in there and little to no wind within. – Loduwijk Jun 28 '18 at 19:37
  • My library would have had to order it through inter-library loan from the West Coast somewhere, and they estimated it would take three weeks. So I ordered a like-new copy from Amazon which will arrive on July 9. – ab2 Jun 29 '18 at 20:13
  • @ab2 Though I didn't expect to so soon, I have since gotten and read the book. It was a good read once I got a chapter or two in, and I did not want to put it down. Instead of answering, I will provide the information to you since you have put a lot of time and effort into this and I do not want to diminish that... ironically, it appears that the "-148" actually comes from the fact that they had a wind-chill chart that only went down to -148, so their wind-chill was off the charts and they just used the lowest number on it. They did have a thermometer with them, temps are mentioned at times... – Loduwijk Aug 03 '18 at 21:01
  • I will add more information later when I have the book on me. – Loduwijk Aug 03 '18 at 21:01
  • Thanks, Aaron. I had a lot going on at home, read the book, and started to revise my answer then forgot about it. I suggest you write an answer based on the book. I will upvote it. – ab2 Aug 03 '18 at 22:49

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From an ad for the book on the website of the AMC Store:

In 1967, eight men attempted the first winter ascent of Mount McKinley, now known as Denali. They faced winds in excess of 150 miles per hour and temperatures more than fifty below zero. The windchill temperature reached –148°. Three team members reached the summit only to be trapped at more than 18,000 feet by a six-day storm. In an ice cave less than a thousand feet below, their teammates waited helplessly until all hope ran out, and the three above were left for dead.

Going to Online Conversion.com, two formulas are given, one used pre-2001 and the other post 2001. The conversion gives

Old Wind Chill minus 67.42 F and New Wind Chill minus 122.69 F

The Old Wind Chill number is obvious nonsense, but the New Wind Chill is post 2001, so would not have been available to Davidson.

The windchill calculator on the National Weather Service website, says it cannot calculate windchill for a windspeed of greater than 110 mph. Plugging in 110 mph, one gets a windchill of minus 147 F for a T of minus 70 F. But this calculator uses the new formula. Ah well, let's see if the book is available from my local library.

ab2
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  • It is likely impossible to come to an exact number, especially when we do not have exact numbers for the known values. We will likely have to settle on the best estimate we can, and it looks like you are narrowing in on it quite well. – Loduwijk Jun 28 '18 at 14:15
  • Though I may be wrong, I would assume the " > 150 mph" were gusts rather than the average. Still, after plugging in some numbers to the calculator to get a feel for the correlation, I would be willing to accept that the "-148F" figure was reached using the 150mph wind estimate. That seems especially likely both to improve dramatization for the publication (not to knock it, as near-death is dramatic), and I can easily see myself or others using the highest estimated gust speeds when retelling our tail. So it is probably safe to go with the ">150mph" for the calculation. – Loduwijk Jun 28 '18 at 14:28
  • I just made a spreadsheet which included that wind-chill formula. I would guess the weather service's calculator might not accept values outside a given range because it is less accurate outside that range. However, the formula provides -66F @ 150mph = -148F wind-chill. ">150" would then be ">-66F". So we have a lower bound of -70 and a crude estimate of 60-ish? – Loduwijk Jun 28 '18 at 14:45
  • However, the book was written before the 2001 update you mentioned... so I should back up and look at what the person who made the original estimate would have used. – Loduwijk Jun 28 '18 at 14:46
  • The "old wind chill index" on that first calculator seems completely broken for these extremes. Putting in higher speeds is making the wind-chill temp warmer at a certain range - not trustworthy. I have asked for help from earth-science.SE here: https://earthscience.stackexchange.com/questions/14511/what-method-would-be-used-to-estimate-a-wind-chill-temperature-in-u-s-1969 – Loduwijk Jun 28 '18 at 15:05
  • I will order the book from my local library. Someone may have the answer before I get and reread the book (which I want to do anyway), but if not, we will have the original source. – ab2 Jun 28 '18 at 16:01
  • Thank you. I will probably read it at some point, but even so I wouldn't be able to get to it soon. – Loduwijk Jun 28 '18 at 19:55