Lake Tahoe and El Niño: OpenSnow.com forecasters sound off
Fall is in the air and the El Niño winter hype machine has begun. Will this be the end of four down snow years in the Tahoe Basin? Whether it’s bar-room discussion or the video loop of old forecast clips currently playing on Heavenly Resort’s website, word is out — and the word appears to be Godzilla. With some forecasters calling for the potential for the biggest El Niño event on record, the Tahoe Daily Tribune spoke with OpenSnow.com founder and forecaster Joel Gratz and Tahoe region forecaster Bryan Allegretto to pull back the curtain on hype and look ahead to winter.
Both experts said they couldn’t say for sure, but there are some positive indicators for substantial precipitation; and the next month may do a lot to clear the weather picture.
“Anyone who tells you they know is lying,” Allgretto said of the hype so far. “We’ll know better as we get into December. As much as we want to be excited, we’re cautiously optimistic.”
As for Godzilla — the term that has been embraced by some outlets for this particular El Niño’s potential— Gratz said, “It’s not anything that’s official and it’s probably not even that relevant.”
He said the term was used by one meteorologist describing the potential and has since been embraced by media and the ski resort community.
“We’re still many months away from knowing if this is the strongest,” he explained.
What is certain at this point is that it will at least be a strong El Niño, because central Pacific Ocean waters are already 2.5 degrees above average. Temperatures would have to reach over 3 degrees above average to be the strongest on record, Allegretto said. But the big questions is how other factors will influence the weather.
Only twice in the last 50 years — 1982 and 1997 — have El Niño water conditions been similar in the central Pacific, and they both yielded strong winters for the West. But other factors in the current pattern are different.
“I don’t think we’ve seen it like this before,” Allgretto said, referring to another warm water mass in the eastern Pacific that could potentially redirect moisture away from the Tahoe Basin and the Sierra Nevada.
“If they looked the same I’d be running around and saying absolutely,” he added of the potential to predict an above-average winter. “Where we sit right now, I would say Tahoe is on the border.”
Their current forecasting model predicts Southern California getting above-average precipitation, but Northern California is less certain.
Allegretto further explained that the warm water mass in the eastern Pacific has been cooling in recent weeks, which could help El Niño weather patterns to deliver more moisture to the Sierra Nevada.
“The faster the eastern Pacific cools, the better our weather pattern. I feel better each week as I’ve been watching,” he said. “Week after week it’s starting to look more like those (two) years.”
Whether that precipitation would fall as rain or snow also remains a variable.
“El Niño tips the odds, but it’s far from a sure thing,” Gratz said of the potential. “Tahoe always flirts with the rain-snow line.”
Allgretto added, “I’m more confident that it’s going to rain a lot than it’s going to snow a lot,” at this point. But the potential for substantial snow remains.
Heavy winter snowfall will also depend on where individual storms go as much as the overall weather pattern, Gratz said.
“Over half the snowfall usually comes from 10-20 percent of the storms,” he explained of patterns in El Niño years.
So Tahoe remains a question mark, but Allegretto said there’s at least a strong chance of an average winter, which alone would be a welcome change from recent years.
Less than 300 inches of snow fell on Donner Pass each of the last three winters. That’s below 75 percent of average, Allegretto said.
“It’s looking OK. It’s looking decent. We don’t want to go all in yet,” he explained. “We’re starting to lean towards a better-than-average chance. We’ll know better as we get into December.”
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