Forecasters say that strong storms are coming to both the East and West coasts on Tuesday. California, which has been hit by storms, could see “catastrophic” flooding, while the Northeast is getting ready for a strong nor’easter.

The National Weather Service said that a coastal low was likely to quickly turn into a major nor’easter that will have a big effect on the Northeast through Wednesday.

Early Tuesday morning, the weather service warned that rates of 2 to 3 inches or more per hour and strong winds would make it “dangerous to impossible” to get around. It said that the snow would likely cause power outages and damage to trees because it would be heavy and wet, and the wind would gust up to 55 mph.

By early Tuesday, bad weather was already making it hard to get around. Due to snow and ice, Delta Air Lines had to stay on the ground at LaGuardia Airport until at least 6:30 a.m. ET.

It said that parts of New England and Upstate New York could get 12 inches or more of snow, and some places could get as much as 24 to 30 inches.

In a statement, the National Grid said that its storm readiness team was “watching the weather forecast and getting ready to make sure the energy delivery system is reliable” before the nor’easter.

As it moved up the East Coast on Monday night, the nor’easter brought heavy rain to Philadelphia. Five counties in New Jersey were in a state of emergency because of the weather, and the National Weather Service said that up to a foot of snow could fall along I-80 in Pennsylvania.

There is a danger to “lives and property” in California

In California, the National Weather Service said that too much rain in the central and southern parts of the state could lead to “severe, widespread flash flooding” that could endanger “lives and property.”

The warning came as the weather service predicted that a front stretching from the Northern Rockies to Central California would bring a wave of low pressure over the Golden State on Tuesday.

Parts of California are likely to get a lot of rain from the storm, while high-elevation areas will get a lot of snow. It also said that there would be a lot of rain in Oregon and the Great Basin.

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The weather service said that as the bad weather moves south across much of the California Coast, Central Valley, and Sierra Nevada foothills, it could cause flooding that is “locally catastrophic” in some places.

The weather service said that heavy rain and snowmelt in areas below 5,000 feet will make flooding worse from Tuesday to Wednesday, especially in low-lying areas and places where there isn’t much snow.

The weather service said that heavy rain that gets soaked up by the deep snowpack in the Sierra Nevada and heavy snow that falls above about 7,500 feet will add to the problems caused by the snow load.

In preparation for the storm, the Weather Prediction Center of the weather service issued a “High Risk” of heavy rain in parts of Central and Southern California through Wednesday morning.

“Flash flooding will happen in places that don’t usually get it,” the weather service said, adding that “lives and property are in great danger from Tuesday to Wednesday.”

“Strong winds that could cause damage, power outages, more flooding, and road closures are all expected,” the National Weather Service said about the San Francisco Bay Area from Monday night to Tuesday.

“Avoid unnecessary travel and complete all preparations as soon as possible,” it said.

The National Weather Service said that by Thursday morning, the threat of heavy rain in parts of Southern California and the Southwest would be down to a “Marginal Risk.”

California is trying to deal with a string of storms.

The new round of bad weather comes after the weekend, when there was a lot of flooding and strong winds.

At a news conference on Monday, officials said that first responders, including members of the California National Guard, had saved more than 200 people in lowlands north of Salinas. One video showed a member of the Guard helping a driver out of a car that was stuck in water.

Monterey County, which is a national center for agriculture, was hit hard by the storm over the weekend. About 2,000 people in the town of Pajaro were told to leave after a 300-foot hole opened up in a nearby river levee early Saturday, officials said.

Monday, Maia Carroll, a spokeswoman for Monterey County, said that a second, smaller breach happened near the mouth of the river. Officials think this one might be good.

She said, “The water is going to the ocean, which stops flooding upstream.”

Also, on Monday, the National Weather Service in Sacramento confirmed that a tornado hit the area around Tuttletown, which is about 50 miles west of Yosemite National Park. Forecasters said it was an EF-1 vortex, which means it had winds that stayed strong for at least 79 miles per hour. The weather service said that the tornado was accompanied by strong storms and hail.

This story was first posted on NBCNews.com.

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