California is experiencing one of the driest starts to spring in decades, data showed Friday, and absent a heavy dose of April and May showers the state’s drought will deepen and that could lead to stricter rules on water use and another devastating wildfire season.

New readings showed the water in California’s mountain snowpack sat at 38% of average. That’s the lowest mark since the end of the last drought in 2015; only twice since 1988 has the level been lower.

State officials highlighted the severity of the dismal water numbers as they stood at a snow measuring station south of Lake Tahoe, where the landscape included more grass than snow. At the deepest point measured there, there was just 2.5 inches of snow.

The deluge California received from a powerful atmospheric river made streams and waterfalls come alive while coating mountains with snow, but as the storm headed east to the Plains on Tuesday it left the Golden State still deep in drought.

The atmospheric river, a long plume of moisture pulled in from the Pacific, capped a series of back-to-back storm systems that abruptly switched the state’s immediate emergency concerns from wildfires to flooding.

But the long-term problem of a drought that scientists say is part of a warming and drying trend driven by climate change was not washed away.

A weather-roiling La Nina appears to have emerged across the equatorial Pacific, setting the stage for worsening droughts in California and South America, frigid winters in parts of the U.S. and Japan and greater risks for the world’s already strained energy and food supplies.

The phenomenon—which begins when the atmosphere reacts to a cooler patch of water over the Pacific Ocean—will likely last through at least February, the U.S. Climate Prediction Center said Thursday. There is a 57% chance it be a moderate event, like the one that started last year, the center said. While scientists may need months to confirm whether La Nina has definitely returned, all the signs are indicating it’s here.

Thousands of Central California farmers were warned Tuesday that they could face water cutoffs this summer as the state deals with a drought that already has curtailed federal and state irrigation supplies.

The State Water Resources Control Board notified about 6,600 farmers in the Sacramento-San Joaquin Delta watershed who have rights to use water from the Central Valley estuary of “impending water unavailability” that may continue until winter rains come.

California Gov. Gavin Newsom this week expanded a drought emergency to a large swath of the nation’s most populous state while seeking more than $6 billion in multiyear water spending as one of the warmest, driest springs on record threatens another severe wildfire season across the American West.

The Democratic governor said he is acting amid “acute water supply shortages” in northern and central parts of California as he called again for voluntary conservation. Yet the state is in relatively better shape than it was when the last five-year drought ended in 2017, he said, as good habits have led to a 16% reduction in water usage.