Snow forecast for mountains tonight

Think it's cold? You have good reason.

Seattle just experienced the coldest first week of June, according to climate records dating to 1891, said Cliff Mass, University of Washington metrologist. Both 1999 and 2008 share the record, with 1917 falling in second place, he said. "Just wait until tomorrow," he said, when temperatures are going to be even colder.

A heavy snow warning has been issued for the Washington Cascades and Olympics as a storm from the Gulf of Alaska plows into the state tonight.

Forecasters with the National Weather Service said up to a foot of snow may fall in the mountains as low as 3,000 feet, which means Snoqualmie Pass may get a dusting.

State transportation crews will be parking their mowers and driving snowplows.

"We will have crews working through the night, and we'll have extra crews on standby just in case this storm hits hard," said Monty Mills, Washington Department of Transportation maintenance manager for snow and ice operations.

Crews will be on the roads today and tonight applying de-icer as necessary to prevent the road surface from icing up.

The state has four snowplows available over White Pass on Highway 12 and seven on Snoqualmie Pass on Interstate 90.

For the last few weeks, crews have stopped fighting snow to mowing grass, tackling weeds, striping lane lines and sweeping roads. It's back to winter operations tonight.

"In 30 years I can only remember two other times when it snowed this late in the season," said Sam Krahenbuhl, Snoqualmie Pass assistant maintenance superintendent. "One time it snowed on a Fourth of July weekend. This is really rare."

While it won't snow in the Puget Sound area, records for the lowest high temperature may be broken today and Tuesday. Forecasters said the high temperature today should be 57 degrees, 1 degree below the record set last year. On Tuesday, under windy and rainy skies, the temperature should only get to 54 degrees, 2 degrees below the record set in 1972.

"It's not completely unusual to get snow in June," said forecaster Dennis D'Amico. "But this is a lot of snow and it's an unseasonable cold system."

Said Mass: "People are really upset about this weather."

He said in the mix of all the statistics, he's put together the "barbecue" index. That's the number of times since March 11 (the usual start of spring here) temperature climbs to 60 degrees or more — a temperature that Mass thinks people are comfortable being outside in.

"It turns out that this year was the worst year of the barbecue index since 1917," said Mass. "We only got to 60 degrees 23 times this year. Compare that to 1934 (74) times or 1992 (69) times."

Mass said the coldest spring was 1917. This year is tied with 1908 for 2nd coldest, he said. The warmest spring was 1934.

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com