12/31/2008

If there are two words to sum up the month of December, they would be cold and snowy. Storm after storm hit the state, and with the temperatures being so frigid, record amounts of snowfall resulted. After a warm and dry start to the month, the first system moved in on the 12th, bringing cold temperatures behind it. Cold, arctic air gripped the state, causing streaks of consecutive days without high temperatures reaching above freezing. Wenatchee had 14 consecutive days with highs below freezing (12/14-12/27) and Stampede Pass, Spokane, and Yakima all had 13 consecutive days with highs below freezing (12/14-12/26). Temperatures on some days in Yakima were down to 21 degrees Fahrenheit below normal and 25 degrees Fahrenheit below normal in Spokane! The last time Wenatchee had 14 days of highs below freezing was in 1980 (1/18-1/31). The 13 day streak of highs below freezing hasn't been seen at Stampede Pass since 1981 (1/24-2/5), at Spokane since 2003/2004 (12/27-1/8), and at Yakima since 2005 (12/7-12/19).

Temperatures warmed to normal in much of the lowlands of western WA towards the end of the month (see Figure 1) so the low pressure systems that hit the state brought much-needed rain to the lowlands, but eastern WA experienced snow right through the end of the month. Numerous daily and 24-hour records were broken in the second half of the month, and some of those records can be found in Table 1. The temperature records are in Fahrenheit and the snowfall is in inches. December 2008 is now both the snowiest December and the snowiest month on record for Spokane (its 61.5 inches beats out the 42.7 inches in December 1996 and the 56.9 inches in January 1950). Snowfall records have been kept in Spokane since 1893.

Please see our January 2009 newsletter for more information on this event.

Figure 1: Temperatures at Sea-Tac for the month of December compared to normals (from NWS). Notice the below normal temperatures in the middle of the month.

Table 1: Examples of some of the daily records broken during the cold and snowy period in December (from NWS). Temperatures are in Fahrenheit and snowfall is in inches.