Another storm will take aim at the Eastern Sierra this coming weekend and another early next week, putting an end to unseasonably warm and dry March and dumping as much as “a few feet” of snow on the Sierra crest by the time April rolls in next Tuesday.
Although the most recent storm Wednesday and Thursday came in a bit lighter than forecast, the next storm coming in on Saturday is forecast to be stronger than earlier forecasts had indicated and the last storm, on Monday, even larger, according to Howard Sheckter, Mammoth’s amateur weather forecaster.
“The next storm for Saturday is on track to bring about a foot to a foot plus over the upper elevations Saturday afternoon/night,” he said. “The following storm for Monday afternoon is much larger now, showing up… as a storm capable up to two-feet plus.
"As is often the case, the third in the series is the biggest as it often has the most upstream amplification. This system has an initial confluence of the subtropical jet and it could really have explosive development.”
That might not be the end of it, either.
“Thereafter… the models still have more storminess in our future, well into May,” he wrote on his website. “The Sub-Climate model…shows six to seven inches of water between today and the 10th of May. That would be another 60 to 70 inches of snow at 10:1. Better late then never?”
Although the “models are still struggling” with where the third storm will hit the West Coast the hardest, NWS meteorologist Tony Fuentes said the Sierra is likely to get a strong shot of moisture.
“There is quite a bit of moisture associated with this one,” he said Monday afternoon. “It’s associated with a tropical plume that reaches all the way to Hawaii, so yes, you could call it a “Pineapple Express.”
"If it comes in near you, the best case scenario is a couple of feet of snow.”
That "best case scenario" is a tantalizing thought for an area left parched and dry by three drought winters, but Fuentes interjected a note of caution, saying forecasting storms in the spring is unusually difficult, due to the fact that spring is a “transition season.”
“We can really only pin down the amount of snowfall about one to two days out,” he said.
But then he added, “I wouldn’t be surprised to see a couple of feet by Tuesday.”
Anything will be welcome. In Mammoth, the snowpack had inched up to 16.6 inches of water at last count on March 18 before the most recent set of storms rolled in—roughly translated to about 16 feet of snow since the winter began. The average moisture content for the Mammoth Pass, where the measurements above were taken by the Los Angeles Department of Water and Power, is about 39 inches for mid-March.
The current snowpack's water content is still higher than the driest winter on record—1976-77, where the total water content was less than ten inches—but at press time, it was coming in as the second driest winter on record.
The average snowpack across the entire Sierra range—an average of all the regions from the mountains north of Tahoe Lake to Lake Isabella near the end of the Southern Sierra—is about 28 percent of normal for mid-March.