02 Arizona flash flooding
Why flash floods are so dangerous
01:06 - Source: CNN
CNN  — 

A series of Pacific storms will bring heavy rain, extreme winds and deep snow to California through the week.

These rains could lead to mudflows in areas burned by wildfires earlier in the year. A mandatory evacuation has already been issued for residents in the Holy Fire burn area.

A rough week in store

  • Up to 6 inches of rain are likely to fall on the coast and valleys and one or more feet of snow will pile up in the mountains.
  • A foot of snow is expected in the Southern California mountains with several feet in the Sierras.
  • Flash flooding will become a concern, especially in urban areas.
  • There is a threat of mudslides and mudflows, especially downhill from burn scar areas in all parts of California.
  • Winds could gust over 40 mph across the valleys and could reach over 60 mph in the mountains.
  • Significant travel delays at major airports and on the roadways are likely throughout the week.
  • The strongest of the storms will be Wednesday and Thursday.

Storms have begun impacting California

It rained much of Monday across Southern California, with locations in and around Los Angeles already seeing about one inch of rain. Transportation officials said a mudslide closed a portion of the Pacific Coast Highway in Malibu.

Rainfall into Tuesday will generally be light and scattered before it begins to increase in coverage and intensity later in the morning.

Flash-flood watches are in place for parts of Orange, San Bernardino, Riverside and San Diego counties, with more than an inch of rain expected. Even higher amounts are expected on the south-facing mountain slopes.

southern california precipitation 01142019

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The coastal ranges across Central California could get as much as an inch and a half with this first storm.

Light precipitation will move through Northern California overnight Monday into Tuesday.

As if the rain wasn’t enough of a concern, Interstate 5 was closed at Tejon Pass – roughly 70 miles northwest of downtown Los Angeles – because of heavy snow.

The worst of the weather will be Wednesday

The second and third rounds of heavy rain will begin late Tuesday and last through Thursday.

The National Weather Service in Los Angeles is expecting a steady rain with heavier downpours during this period. An additional few inches of rain could fall across the region.

northern california precipitation 01142019

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During this time the Sierras will get the most snow, with the heavier snow piling up on Wednesday and moderate snow continuing to fall on Thursday.

The strongest winds across the state will peak on Wednesday and begin to decrease Thursday.

The region will begin to dry out again on Friday. The storm system then moves east into the Central and Eastern United States over the weekend.

CNN Meteorologist Monica Garrett contributed to this report.