Snowpacks low across the west, no miracle March snow fall in prospect.
It’s not a stretch to say that what’s bearing down on the Western United States over the next ten days will be the most extreme March heatwave the region has ever seen in US history, not just in intensity, but in duration.
This isn’t a brief warm spell. This is an extended, unprecedented siege of heat arriving months ahead of schedule.
The amount of territory that will be covered by a record-strong high-pressure ridge or “heat dome” next week is astonishing. The entire region highlighted in pink will experience its strongest high pressure ridge on record for this time of year.
Almost every major city in the West has a shot at shattering its all-time March temperature record: Los Angeles, San Francisco, Phoenix, Las Vegas, Denver, Salt Lake City, San Jose. Many of these cities won’t just edge past old records by a degree or two, they could obliterate them.
Phoenix may be the most staggering example. The city could reach 105°F next weekend. That would not only break its previous March record by a full five degrees, but would also tie its all-time April record.
Las Vegas will see similarly extreme heat. The city’s all-time March record is 93°F, yet the National Blend of Models (NBM) is forecasting that Las Vegas could break that record not once, but five times over the next 10 days, with some model runs pushing temperatures up to 100°F. That would place temperatures 7 degrees above the previous monthly record.
The warm-up is bad news for the state’s snowpack, sitting at just about 53% of average for this time of year — and melting daily. After an exceptionally warm winter, state officials said the rapidly melting snowpack is complicating efforts to preserve the state’s water supply, and climate experts claim the loss of snow early could increase wildfire risk in the northern part of the state.
Daniel Swain, a climate scientist with UC Agriculture and Natural Resources, said it’s clear from the warm forecast that “there will be no Miracle March,” or when a dry winter turns into a snowy one with late-season cold storms.
“We’re going to get to April 1, and we’re going to have some scary snowpack numbers, essentially everywhere,” Swain said in his latest YouTube office hours.
Swain said the above-average heat is “not going to be a short-duration heat wave” and could last two weeks, even though it “won’t be equally hot the whole time everywhere.”
A record snow drought with unprecedented heat is hitting most of the American West, depleting future water supplies, making it more vulnerable to wildfires and hurting winter tourism and recreation.
Scientists say snow cover and snow depth are both at the lowest levels they’ve seen in decades, while at least 67 Western weather stations have measured their warmest December through early February on record. Normal snow cover this time of year should be about 460,000 square miles — about the size of California, Utah, Idaho and Montana — but this year it’s only California-sized, about 155,000 square miles, according to the National Snow and Ice Data Center.
“I have not seen a winter like this before,” said center director Mark Serreze, who has been in Colorado for almost 40 years. “This pattern that we’re in is so darned persistent.”
