February 2, 2010
Portland Decadal Snowfall Update
When history looks back on the winter of 2009/2010, it will look like a massive arctic blast with snow in December. However, upon closer inspection, it will actually be a good old fashion El Nino winter with only 2.5" of snow at the NWS forecast office in Portland (as of 1/31/10). None of which came with the "actual" December arctic blast. One might call the winter of 2009/2010 "the winter of the wasted arctic blast." After all, it was one of the coldest arctic intrusions (for so early in the season) on record.
However, we did receive more snow during winter 09/10 (2.5" as of 1/31/10) than we did in 99/00 (only 1"). In fact, since this was a moderate El Nino winter, we actually over performed in the snow category. As pointed out at the annual AMS meeting at OMSI last October, research shows that Portland averages only 0.7" of snow in an 09/10 winter that featured an El Nino. If this had only been a La Nina winter, it could have been huge for snow lovers! The La Nina 09/10 average snowfall at Portland over the last 140 years is 20"+. We can thank good old El Nino for spoiling the fun.
But, it is not all doom and gloom! Our total decadal snowfall in Portland from 2000-2010 was the highest since 1970-1980! This decade was also the third decade in a row where the totals have increased over the previous decade, although increases were very minor. 1980-1990 was the worst snowfall decade in history for Portland!
The "Glory Decades"
1871-1880 = 183.2"
The winter of 09/10 also took a bit of a "hit" on the "top spot" designation that it has held over all other winters. We are now very close to the 02/03 winter average snowfall. If it had not been for the 24.2" of snow last winter (2008/2009), Portland would have been sitting around 25" for the entire 2000-2010 decade, thus the worst in recorded history.
PDX Winter Snowfall Averages (through Jan 31st 2010). Period of record 1871-2010
09/10 = 13.8" (through Jan 31st 2010)