Hilary, the first tropical storm to move into Southern California since 1997, marked the first time ever that tropical storm watches were issued in the region.

Sunday set a new record for the wettest August day ever in Palm Springs, San Diego and downtown Los Angeles.

Hilary's highest rain total was in Upper Mission Creek in San Bernardino County, where 13 inches of rainfall was recorded.

-ABC News' Melissa Griffin

In Forest Falls, California, about 700 people are sheltering in place after mud and debris flow cut a road off from the rest of the community, according to the San Bernardino County Fire Department. No injuries were reported and crews are working to restore road access, the fire department said.

In nearby Seven Oaks, another 30 people are sheltering in place after flash floods struck several cabins in the area, the fire department said. Crews are working to access the residents and evacuate them, the department said.

All tropical storm warnings have been canceled across Southern California as the remnants of Hilary, which no longer meet the threshold of a tropical cyclone, track north, according to Ariel Cohen, meteorologist in charge at the National Weather Service Los Angeles.

Residual mudslides and rockslides are still a threat in California from the weekend rain.

The moisture from Hilary is now moving through the Rockies. On Monday, the flooding threat will be from the Sierra Nevada mountains into the northern Rockies in Idaho and eastern Oregon.

Los Angeles "avoided a potentially catastrophic set of conditions" from Hilary, LAUSD Superintendent Alberto Carvalho said Monday.

Carvalho defended the decision to close LA's public schools on Monday citing reasons including that many students walk to school and many employees live outside of LA.

"It would have been reckless for us to make a different decision" on Sunday, he said.

Schools appear to be in good condition, he said, noting that about 24 schools don't have phone or internet access and one elementary school that serves students with disabilities appears to have been impacted by a mudslide.

Carvalho said students should expect to resume their regular school day on Tuesday.

FEMA Administrator Deanne Criswell told reporters she is providing "continuous updates" to the White House about preparations ahead of the storm.

Criswell said she has also been in contact with California Gov. Gavin Newsom and Nevada Gov. Joe Lombardo to discuss "what type of support that they may need from FEMA and the federal family, but also to remind them that we are ready to support them as needed for this storm."

Criswell said they will not be moving any resources from Maui to California or Nevada to respond to the storm.

"We are still fully engaged in our efforts to help the state and people of Hawaii recover but it's also equally important that we are making sure communities that are in the path of Hilary also have the resources that they may need, and to what is likely going to be heavy impacts from rain and flooding," she said.

-ABC News' Justin Gomez