Fast melt-off in May wipes out most of snowpack
The snow at high elevations in the Cascades has vanished completely, about three weeks ahead of normal.
In just one month of unseasonably warm temperatures, the ample snowpack at Harts Pass went from 79 inches (111% of normal) on May 1 to 11% of normal at the end of the month. Snow at the 6,500-foot site had melted entirely by June 4.
The early melt-off means that central Washington is at elevated risk for significant fires, even in June, according to a briefing by fire officials from the Okanogan-Wenatchee National Forest on Monday (June 5).
The winter started with copious snow, but February brought little precipitation and the snowpack started to dwindle until a cool and wet April briefly replenished it, according to the Washington Snow Survey Office of the Natural Resources Conservation Service (NRCS). Still, that was no match for record-breaking temperatures in May.
“That warm May just killed us,” NRCS Water Supply Specialist Scott Pattee said. Despite extra snow in April, “once it started melting, it was like a freight train,” he said.
Both Mazama and Winthrop broke records on May 20. The 87 degrees recorded in Mazama broke the record by 5 degrees, and Winthrop’s high of 89 surpassed the previous record by 1 degree, according to the National Weather Service.
Not all areas in the Cascades benefited from the winter’s moisture. Snowpack at Rainy Pass peaked on April 24, but it never reached normal this year, Pattee said. Rainy Pass had 59 inches of snow on May 1, just 82% of normal. All that snow was gone on June 1.
Pattee has paid extra attention to soil moisture since the ground at Harts Pass and other areas in the mountains started the winter drier than ever. After a summer with little precipitation, the soil is usually replenished by fall rains, reaching 60% moisture content before it snows. But last fall was so dry that soil at Harts Pass had just 6% moisture content, Pattee said. Soil at Rainy Pass is also “doom and gloom — below what we have ever seen,” he said.
The soils were briefly saturated in April and early May from snowpack and some rain. But that moisture proved short-lived, with soils drying out again as soon as the snow was gone in early June, Pattee said.
Elevated wildfire risk
June is also expected to be warmer than normal. East of the Cascades, there’s an equal chance of June precipitation being above or below normal, but typically wetter Western Washington is expected to get less precipitation than usual. The entire state will be drier than usual for the rest of the summer, according to the Okanogan-Wenatchee fire staff.
That translates into an elevated risk of significant fires from July through September for all of Washington and for eastern Oregon.
The hot, dry May obliterated benefits from the previous six months, which were cooler than normal across the state, Okanogan Wenatchee Forest Fire Staff Officer Kyle Cannon said. While there’s not a lot of correlation between snowpack and fire season, there is a correlation between the timing of snowmelt and fire potential, he said.
The Okanogan-Wenatchee has 345 firefighters on board and is still hiring for the season, according to the fire officials. The North Cascades Smokejumper Base is fully staffed with 30 smokejumpers, more than in recent years.
The forest has three helicopters, compared with four last year. They hope the fourth helicopter will be deployed locally, according to the briefing.
There are six crews for initial attack, and nine of 11 fire engines are staffed. Air tankers are stationed in Moses Lake and in Wenatchee. The Okanogan-Wenatchee fire team said they feel “pretty good” about staffing, compared to the rest of the country.
On average, there are 110 fires annually in the Okanogan-Wenatchee National Forest, but that can vary greatly and isn’t indicative of fire severity. Last year, there were 83 fires, which burned just over 11,000 acres. The largest fire was the Northwest Pasayten Complex near the Canadian border, which burned more than 29,000 acres, but smaller fires closer to population centers had a greater impact.
In 2021, there were only 70 fires in the Okanogan-Wenatchee, but they burned almost 189,000 acres. In 2019 and 2020 combined, just 5,300 acres burned in all. The year with the most acres consumed by fire in the past two decades was 2017, when 233,637 acres burned.