(CN) — After one of the wettest Decembers in recent memory, January and February have been among the driest ever. And it appears unlikely to change any time soon.
"January precipitation was a bust. February is looking the same," the National Integrated Drought Information System said in a status update Thursday. "Drought intensification is likely, and impacts may be severe for some areas."
A high pressure ridge near the West Coast has largely diverted precipitation away from California, Nevada, Oregon, Washington state and Idaho over the past six weeks, according to the agency. As a result, reservoir levels are already extremely low in southern Oregon, and in California the volume of water stored in the snowpack and reservoirs combined has plateaued.
The five western states are on "the precipice of drought intensification" if precipitation continues below normal — a prospect forecasts and historical odds indicate is likely, according to the status update.
The region is stuck in a megadrought that has enveloped southwestern North America for the past 22 years. The current megadrought, which is defined as drought last two decades or longer, is also the driest the region has gone through for more than 1,200 years, according to a recent study led by UCLA.
December through February are California and Nevada’s wettest months, the agency said, and the extended dryness over the past four to six weeks has caused California's "snow water equivalent" to plunge to the same level as this time last year, also an abnormally dry year. In Nevada the amount of water in most basins has plateaued as well. Current measurements indicate that the Sierra Nevada show water equivalent is 71% of normal for this date and most of California's reservoirs remain below historical average.
Listen to our podcast episode on the historic drought plaguing the U.S. West, "The Dry, Dry West"
Often called California's "frozen reservoir," the Sierra snowpack supplies nearly a third of the state's drinking water throughout the year. Last year, exceptionally warm temperatures melted the snowpack months early and dismal amounts of runoff were captured by the state’s critical reservoirs, spurring Governor Gavin Newsom to urge residents to voluntarily slash water use.
If it doesn't rain in February, the odds that California will have a normal amount of precipitation this year falls to 10%, according to the update.
And then there's the wildfire risk. The severity of the West Coast drought was illustrated by an unusual January wildfire in California's Big Sur.
California and the other West Coast states have been beset by wildfires in recent years as changing weather patterns, rising temperatures and prolonged drought have combined with years of forest mismanagement to create conditions ideal for large high-severity fires.
But it is extremely unusual for evacuations due to wildfire to be called for in January, a time when firefighters can typically set aside their equipment and rest up for a fire season that historically doesn’t ramp up until May at the earliest.
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