All along from Interior Alaska to West Texas, this positioning produces a winter climate influenced by “chinooks”, warm adiabatic winds descending from mountains over 4,000 metres high. When chinooks are present, winter temperatures can be extremely warm relative to long-term averages, creating temperature variation over this “chinook belt” that are not rivalled anywhere else in the world. For instance, although the mean January temperature in Fairbanks is -10˚F or -23.3˚C, absolute maxima are as high as 10˚C or 50˚F. In contrast, in East Asia places with similar average January temperatures seldom if ever top freezing. Further south in the “chinook belt”, similar contrasts continue: at Havre, Montana where the mean for January is around -9˚C or 16˚F the record maximum is 68˚F or 20˚C whereas Shěnyàng with a similar average has never exceeded 8.6˚C, and Rapid City in South Dakota with an average of -3˚C has an absolute maximum of 24˚C – hotter than Melbourne’s absolute midwinter maximum of 22.2˚C.
|Global temperature anomalies for February 1954 relative to 1880 to 1974 mean, courtesy of Goddard Institute for Space Studies|
|Comparative daily maximum temperatures for Melbourne, Victoria, Australia and Rapid City, South Dakota, United States in February 1954 (˚C)|
If we have a look at the other (more distinctive) side of the “chinook belt” climate – abnormally warm winter days relative to position – we see a different story:
This perception may also explain the strong Republican leanings of the “chinook belt” compared to the rest of North America away from the low-nutrient and naturally conservative non-“Black Belt” South. Like Australians who are used to extremes of drought and flood, people in the “chinook belt” are used to such changeable winter weather than the effects of their own greenhouse emissions may seem much smaller than to people from regions without potential warming Föhn winds in a very cold climate.