Tuesday marks the beginning of a period of snow in the northern tier of the United States.

Up to a foot of snow is possible across the Dakotas by Saturday, with up to 8 inches possible across the Upper Midwest and northern Plains.

While the snow falls in the north, days of rain in the south will increase the risk of flooding.

Flooding is most likely in Oklahoma and northwestern Arkansas on Tuesday, but it becomes even more likely in the region on Wednesday and Thursday.

Snow to the north
Access To San Bernadino Mountains Begins To Open After Residents Stranded For Days By Snow
Mario Tama/Getty Images

While the snow falls in the north, days of rain in the south will increase the risk of flooding.

Flooding is most likely in Oklahoma and northwestern Arkansas on Tuesday, but it becomes even more likely in the region on Wednesday and Thursday, as per Fox News.

The San Bernardino County mountains are among the hardest hit, with emergency supplies running low.

Rescues are taking place, but personnel must use specialized equipment to reach victims, which slows down efforts.

To make matters worse, another atmospheric river is en route to California.

Tuesday marks the beginning of a period of snow in the northern tier of the United States.

Up to a foot of snow is possible across the Dakotas by Saturday, with up to eight inches possible across the Upper Midwest and northern Plains.

While snow falls in the north, days of rain in the south will increase the risk of flooding.

Flooding is most likely in Oklahoma and northwestern Arkansas on Tuesday, but it becomes even more likely in the region on Wednesday and Thursday.

A series of storms dumped feet of snow on California's mountains, leaving residents in desperate need and pleading for assistance.

The San Bernardino County mountains are among the hardest hit, with emergency supplies running low.

Rescues are taking place, but personnel must use specialized equipment to reach victims, which slows down efforts.

To make matters worse, another atmospheric river is headed for the Golden State.

Atmospheric River In California Weather Forecast Could Melt Snow

According to AccuWeather, a significant flood threat is forecast for portions of California by the end of the week as a storm with milder air drops heavy rain over higher elevations that have been blanketed by frequent rounds of heavy snow this winter.

The next Pacific storm is expected to arrive in California later Thursday, into Friday and Saturday, and will be accompanied by a moderately strong atmospheric river, a long plume of moisture stretching back over the ocean, according to the National Weather Service.

People and businesses are already cleaning up after previous storms, which means the latest storm has the potential to become a disaster on top of previous disasters, compounding any effects, according to AccuWeather Chief Meteorologist Jonathan Porter.

More storms are expected into next week, which may also tap into a 2,000-plus mile feed of deep subtropical Pacific moisture, resulting in heavy rain at lower elevations and heavy snow in the mountains

While the latest in a series of moisture-laden storms across California this wet season will bring a variety of life-threatening impacts while increasing the risk of property damage, the storms will also provide additional drought relief, building on the relief provided by previous storms.

Furthermore, UCLA climate scientist Daniel Swain predicted that because soils are now saturated, this storm will likely cause a significant increase in slope failures (such as mudslides, landslides, and debris flows) throughout Northern California.

Swain added that, while this warm and wet storm will cause some flooding, he is more concerned about the risk of additional warm atmospheric rivers following toward mid-March.

"Big problems would begin if we had successive warm atmospheric rivers," he said.

Atmospheric rivers are ribbons of water vapor visible through clouds that extend thousands of miles from the tropics to the western United States.

They provide the fuel for massive rain and snowstorms that can cause flooding along the West Coast and are 250 to 375 miles wide.

In general, atmospheric rivers pick up water vapor from the warm, moist air of tropical regions and drop it as rain or snow over land in cooler regions.