When we look back on the winter of 2014-2015 in years to come, we’ll tell stories about how unusually cold and snowy it was — or wait, no, make that unusually warm and dry. Or actually, both.
SNOW – OR LACK THEREOF
Snow, snow, and more snow, that’s what’s been dominating the headlines the past few weeks. However, other than the most recent winter storm that cut across the middle of the country and cut up along the East Coast, it’s really only a small area of the U.S. that is getting pounded with such high amounts of snow – yes, that’s you coastal New England.
The graphic above shows the % of normal snowfall so far this winter (Dec. 1-Feb. 17) for stations across the country. The record snow clearly stands out around Boston and scattered locations from southern Arizona into the Texas Panhandle. However, just as clear is the stark lack of snow across the West Coast. In fact, Mt. Shasta Ski Park in northern California is temporarily closed until the next storm arrives.
ARE WE SEEING ANY LONG-TERM TRENDS?
These snowfall extremes are impressive, but any given year can have crazy weather. It’s when you zoom out and look at the longer-term picture, as the 2014 National Climate Assessment did, that you see patterns start to emerge. As you can see in the graphics below, mid-latitude winter storms have increased in both intensity and frequency nationally since 1950. Overall, there were twice as many extreme winter storms in the U.S. in the second half of the 20th century as there were in the first half.
This is consistent with what you’d expect in a warming world. Higher temperatures lead to more evaporation from lakes, rivers and oceans, and warmer air can hold more moisture. What goes up must eventually come down, so climate science projects that extreme precipitation should increase. And that's just what meteorologists have observed, not just for snowfall, but for precipitation overall.
NOTE: The analyses behind these graphics are explained in more depth in these two published reports:
RECORD COLD AND RECORD HEAT
It’s not just the snow dominating the headlines, it’s also the cold. If you live in the Midwest or the Northeast, this week started with some of the coldest air in many years, and another bout of potentially record-breaking cold is coming later this week. Out West, however, it’s been one of the warmest winters on the books. Daily records are being set from the Northwest to southern California over to Utah, among other places. So far this year, we are actually setting high temperature records at a blinding pace. To date, record highs have outpaced record lows by 5 to 1 across the country, with 8,389 high records and just 1,703 low records.