Worst Snowstorm Since 1985 Headed for Seattle City could see three times its average annual snowfall By Evann Gastaldo, Newser Staff Posted Jan 17, 2012 11:54 AM CST 17 comments Comments Pedestrians walk across a hill in Seattle during a snowstorm, Sunday, Jan. 15, 2012. Several inches of snow fell quickly Sunday morning, snarling traffic and clogging roadways. (AP Photo/Ted S. Warren) (Newser) – A major snowstorm is expected to hit Seattle tonight, dumping as much as a foot by tomorrow evening. And it looks like things will get worse: Weather.com is predicting up to 18 inches in parts of the Seattle area within 48 hours; MSNBC notes that is three times the city's average annual snowfall of 5.9 inches. Other sections of Washington could see even more—and as much as 3.5 feet could hit the Cascades. In Portland, where the average annual snowfall is 2.4 inches, up to 8 inches of snow are expected. One meteorologist predicts it will be "the biggest snowstorm in years," and another warns of "very adverse, hazardous winter conditions." Mountain driving has already turned dangerous, and other travel could become "dangerous or impossible," says another meteorologist. The Seattle Post-Intelligencer notes that conditions are similar to a highly destructive 1996 storm that caused landslides when the snow turned to rain, as this snow may do tomorrow or Thursday. MSNBC adds that this could be the biggest Seattle snowstorm since 1985.