by: Brian Monahan Updated:
Every morning -- in fact, a couple of times a day -- we get mountain snow reports from the various resorts around western Washington. To say these updates have been depressing -- for skiers and snowboarders, at least -- for most of the winter is an understatement. Remember last month? It's hard to believe it was just a short few weeks ago that snow water equivalent in the mountains -- essentially a measure of how much water is locked up in the snowpack -- was at just around 25 percent over the Olympics and anywhere from 40-60 percent over the Cascades.
Over just the last 10 days, with a breakdown in the persistent high-pressure ridge along the coast of the western U.S., we've really turned things around in the mountains. One to as much as 2 feet of snow fell over the resorts Sunday into early Monday morning, enough snow to shut down a large chunk of Interstate 90 on either side of Snoqualmie Pass. At Stevens Pass, the ski resort just crossed the 100-inch base mark for the first time this season. Checking the snow water equivalent stats this morning, it's not surprisingly a much better story:
• Central Cascades: 74 percent (of average snow water equivalent)
• North Cascades: 84 percent
• Olympics: 69 percent
Not only is this good news for skiers, snowboarders and resort operators, but it's also good news for the lowland water supply later this spring and summer. A healthy water supply is highly reliant upon the melting of a substantial winter snowpack over the mountains. Without that snowpack, the potential would be there for water supply issues and drought-dry weather issues over the lowlands as the warmer and drier months approach. This pattern has gone a long way to alleviating some of those concerns.
Over the lowlands, last night's storm was a prolific rain producer, especially over the southern third of the area. An average of 1-3 inches of rain fell from around Olympia and Tacoma southward, with a solid 1-1.5 inches around the Seattle area. In fact, over the last few days, we've nearly erased our annual rainfall deficit at Sea-Tac airport and are now nearly 2 inches above average rainfall for the month. Most of last night's rain has since dried up -- only scattered showers with some sunshine are expected the rest of the way today.
The wet pattern is not over, though. The next storm is already loading up over the Pacific, and after a rather dry period for most neighborhoods today through tonight, areas of heavy rain will again spread across the Puget Sound lowlands and coast tomorrow morning with an inch or more likely over many neighborhoods from Seattle south. It will be another storm that will have the chance of producing more than 2 inches of rain over the far southern reaches of the area. The wind will pick up again, too, with gusts in the 30-50 mph range likely later Tuesday morning into the afternoon.
Over the mountains, another round of heavy snow will fall. This is a bit of a warmer storm, though, and it's likely there will be a changeover to rain for a period at the passes around midday tomorrow. Still, a solid foot or more of snow should fall at the passes, with up to 2 feet above 4,500 feet. Pass travel will again be very difficult -- if not impossible, at times -- on Tuesday.
After another storm moves through Wednesday night into Thursday, a drier pattern will take hold of the area late this week. In the meantime, though, we'll keep adding to the mountain snowpack and the lowland rain gauges.