A Pineapple Express roared into Washington State Tuesday (1/6), shooting the freezing level up to peak tops, dropping heavy rains, and battering resorts with high winds. Mountain passes closed due to flooding, washouts, mudslides, avalanches, and extreme potential for even more avalanches. Ski areas were closed, and one suffered damage from a slide.
Most of the Cascades received 24-50 inches of snow in January's first few days. But freezing levels on Monday skyrocketed, ushering in heavy rains and strong winds. A foot of rain pelted mountain passes and ski resorts - water that seeped through snow layers, significantly increasing the avalanche danger by Wednesday.
"Rain adds weight to the snow, but no strength," Mark Moore, Director of the Northwest Weather and Avalanche Center, told OnTheSnow.com. "It just loaded a fragile snow pack."
Rains also ate ten inches of snow from the base at Snoqualmie Pass and perked through to the ground. A 300-foot-wide avalanche ripped down the side of Hyak, also known as Summit East, at the Summit at Snoqualmie late Wednesday morning. The four-foot-deep slide scoured the slope down to mud, and toppled two lift towers on Grayson's Run on the Keechelus chairlift.
The slide sprawled debris-snow, mud, brush, and a lift tower-across the base of the Easy Gold lift into a local community of skier homes. Debris struck eight homes, knocking one off its foundation, but only two people were treated for minor injuries.
"We had unusual snow pack structure develop this year with its weakest point at the base of the snow pack. Really cold mountain temperatures just piled up more and more snow on top of that weakness. That set the stage," explained Moore. "We don't often develop that weakness to this extent, and we've been concerned about that deeper instability for some time."
Avalanche and flooding danger had mounted to extreme by Tuesday, forcing the Washington Highway Department to close all mountain passes for safety. Most ski resorts were further isolated by Wednesday evening, cut off by avalanches and mudslides. Water flooded onto roadways, and pavement eroded away in washouts.
"We've had everything from slush flows to debris torrents and mudslides," explained Moore. "Culverts blocked and frozen by earlier cold weather sent stuff along highways, causing structural damage." The road closures shut off access to the Summit at Snoqualmie, Stevens Pass, Mt. Baker, Crystal Mountain, and White Pass.
Mission Ridge was the only resort whose access road remained open, but the resort closed today (1/8) due to winds. The storm, which pounded other ski areas with rain, hit hurricane-force gusts of 121 mph Tuesday night at Mission Ridge.
"Winds sheered off a light tower and snapped off a dozen trees blown onto runs," General Manager Mark Milliette told us. This morning's gusts were still knocking 80 mph, but he expects the winds to abate by tonight, and crews are already out cleaning up.
Forecasts are calling for freezing levels to drop into lower elevations by tonight (1/8), bringing more snow. "We're emerging from the dark woods now," said Moore, noting the avalanche danger is moving into the considerable to high range from the extreme. "We're cooling. Once this heavy dense snow refreezes and settles in place, it'll help."
Milliette also looked forward to reopening Friday (1/9) with new snow. Cooler temperatures also will permit groomers to pack the slopes again. "The rain consolidated the snow pack, which we needed to have happen," he said. "We'll now have a good base, and the new snow will get things healed up again."
Ski resorts plan to reopen as soon as possible, with Crystal Mountain, Mt. Baker, and Mission Ridge aiming for Friday re-openings. Officials recommend checking with the highway department before heading off for the resorts - especially for skiers coming from west of the Cascades where additional flooding has closed down multiple highways and roads. Summit East at Snoqualmie will remain closed.
Check the snow reports here at OnTheSnow.com regularly for updates.