California snow drought ends dramatically, while other states still face shortages
Kalansky pointed out that previous studies have shown that a jump on this scale can occur about twice every three years, but usually over an entire winter, not just December.
Although they do not have the exact ranking for each month of the year, “most of the storms in the study that we referenced for the above calculation occurred in the second half of December and later. in the season, ”Kalansky added.
Parts of California are known for whiplash, but the rapid changes are quite noticeable given that the snowpack has had such a difficult start, after a very hot and dry November for much of the state. .
However, southern California has only recently been able to benefit from one of the largest atmospheric river systems.
“Tuesday’s storm that brought 1 to 2 inches of rain to coastal areas and valleys reduced our rainfall deficit,” the NWS office in San Diego said last week.
The area was so late before last week’s storm that recent precipitation has only brought the area back to where it would normally be at this time of year, rather than ahead.
California is just a western state, and not all states are equal in terms of the humidity received by recent storms.
The Sierras can collect much of the moisture from large storms, but prevent it from entering neighboring states.
Colorado’s snow deficits affect millions more people beyond state borders. When the snowpack melts in the spring, it supplies the water supply to the Colorado River Basin.
Chelsea Peters, a meteorologist at the NWS office in Las Vegas, explained that the Intermountain West snowpack, or lack thereof, can have cascading impacts on the southwestern states, especially if snowpack levels are below average for several consecutive years.
“Several years of below normal snowpack in the Intermountain West Mountains that feed the Colorado River Basin will continue to increase water stress, which was already at risk due to population increases,” said Peters. “We recently saw this impact on reservoir storage and lake levels in Lakes Mead and Powell. Over the past year, Lakes Powell and Mead both saw their lowest storage levels in 30 years. . ”
More thunderstorms on the way
More rain and snow penetrate the west coast thanks to three distinct waves of humidity.
The first arrived in the Pacific Northwest on Saturday, bringing heavy coastal rains and snow to the mountains, creating dangerous travel conditions along the Cascades.
On Sunday, the low will move south into Oregon and northern California.
Snowfall totals will vary from 3 to 6 inches for the northwestern interior states, with up to 2-3 feet for the higher elevations of the Cascade, Sierra, and northern Rocky Mountains. .
An atmospheric river pumps incredible amounts of moisture from the Pacific Ocean to the western states, resulting in very heavy rain and snow.
By Monday and Tuesday, heavy precipitation will spread from Washington to central California.
Over the next five days, widespread rainfall of 2-4 inches is expected along the coasts and lowlands.