Atmospheric River Update: Snowfall Forecast Changes, Pacific Pulse Looms

A stock photo shows the Sierra Nevada mountain range in California. These mountains are set to receive heavy snowfall in the coming days.

Forecasters are now predicting a lot more snow in California as an atmospheric river unleashes winter storms on the state.

Previous forecasts earlier in the week predicted that snowfall could reach upwards of 36 inches in the Cascades and Sierra Nevada mountain ranges. Now, forecasters are predicting “very high probabilities” of snowfall exceeding 48 inches for certain portions of the Sierra Nevada. There is also a potential of it reaching above 80 inches.

Atmospheric rivers are corridors of concentrated, tropical moisture that travel through the atmosphere. When they are unleashed, they result in heavy rain and snowfall. California has seen a series of them recently, which have caused flooding and landslides in recent weeks.

This most recent atmospheric river is set to bring heavy rain and snow through to until at least March 1, with a possibility of it lasting until March 3.

There is potential for a “pulse of integrated water vapor transport” from the central Pacific which could make the atmospheric river conditions last longer, according to the Center for Western Weather and Water Extremes. This means that more water vapor could be transported through the river.

Blizzard warnings are in place for much of the Sierra region, and the National Weather Service has warned of “significant disruptions to daily life.”

Although the incoming weather conditions will be unpleasant, the snowfall could increase snowpack levels in the mountains. Snowpack buildup is essential to water supply for the state, as when the weather warms, it turns into meltwater that feeds into the rivers and reservoirs.

Despite the recent storms, snowfall in the state has been relatively slow and snowpack levels remain below average.

The state has seen some heavy rainfall in recent weeks, caused by a series of atmospheric rivers. However, they did not do much for the snow in the surrounding mountains, and some were relatively weak compared to others.

Last year, several intense winter storms caused a record amount of snowpack in the surrounding mountains which was welcome to the state’s reservoirs, that had previously been at record low levels. It remains to be seen whether this incoming blizzard could raise reservoir levels to match those of last year.

In recent years, California has been in a prolonged drought, which meant water supply was very low in the state. It remains to be seen how it fares for the rest of 2024.

This year is an El Nino year, which usually brings wetter than usual weather to the West Coast. However, experts have also put these increased extreme weather events down to climate change, which seems to be intensifying weather conditions across the globe.

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about atmospheric rivers? Let us know via [email protected].

Related Articles

Start your unlimited Newsweek trial