Mudslides, flash floods and tornadoes in the forecast: Here's the latest on the SoCal storm

This story will be updated. Check back for details.

A strong storm has started to make its way into Southern California, kicking off what could be a perilous four days for the region.

Anywhere from 2 to 5 inches of rain is expected to fall across most of the area, but as much as 8 inches could fall along coastal slopes, including recently burned areas, raising the risk of debris flows, according to the National Weather Service in Oxnard.

The heaviest part of the storm will arrive in Santa Barbara on Thursday night and slowly move southward, with rainfall peaking in Los Angeles some time between Friday and Saturday night.

Evacuation warnings have been issued by L.A. County for the Eaton, Palisades, Kenneth and Canyon fire burn scars. Residents should be prepared to evacuate, as rainfall rates could exceed the debris flow threshold of half an inch per hour. L.A. County is providing updates on its emergency website .

Flash floods, roadway closures and small tornadoes are all a possibility. If you're flying out of LAX, you may experience flight delays due to strong winds Friday and Saturday.

The National Weather Service will issue a flood watch for Friday from midnight through noon for Santa Barbara and Ventura counties.

We'll have a a lull before the second, more intense part of the storm hits, and another flood watch will be in effect for Santa Barbara, Ventura and Los Angeles counties Saturday between 4 a.m. and 10 p.m.

The average amount of rainfall for downtown L.A. in November is 1.23 inches, making the potential 5 inches a surprising amount of rain for this early in the season.

This storm has been difficult for forecasters to predict, as it's a cutoff low, or a low-pressure system that's detached from the more predictable jet stream. As the storm develops, estimates could change. For example, there's a 10% chance that rainfall rates will be under 2 inches for L.A.

As for fire season? We’ll have to get back to you on that one. It’s going to depend on this storm's rainfall totals. Typically, the NWS in Oxnard looks for a widespread 3 to 4 inches of rainfall across the area before they put a bow on fire season. We could be there by the end of the weekend. However, assessments will need to be made after the storm wraps up.

Rainfall estimates

Here are the rainfall estimates from the NWS for much of Southern California from Thursday to Sunday:

• Santa Maria: 3.18 to 4.23 inches
• Santa Barbara: 4.2 to 5.6 inches
• Downtown L.A.: 2 to 4.8 inches
• Long Beach Airport: 2.5 to 4.22 inches
• Orange County: 3 to 4 inches
• Oceanside: 2.5 to 3 inches
• Riverside: 2 to 2.5 inches
• San Bernardino: 2 to 2.5 inches
• Joshua Tree: 1.5 to 2 inches
• Escondido: 2 to 2.5 inches
  

Evacuations and closures

Evacuation warnings have been issued for the Kenneth, Palisades, Eaton and Canyon fire burn scars in Los Angeles County.

A flood watch is in effect for much of Southern California from Friday night through Saturday night.

Forecast

Another milder storm may drop some rain Monday, and we could see some more intense precipitation at the tail end of next week. We'll have updates for you throughout the week.

Take this storm seriously

There are things you can do to give yourself the best chance of receiving urgent messages, such as evacuation orders, during an emergency.

One of the most important is to sign up for emergency text messaging services in your city or county. That’s one of the main ways emergency responders communicate with large numbers of people.

There’s Alert L.A. County , for example. But just 1.6 million people here are signed up — out of about 7.8 million adults. If as an Angeleno you do nothing else to prepare today, sign up for Alert L.A. County.

You should also be aware of the X (formerly Twitter) accounts of your local agencies, as that’s often where they post updates.

Here's a guide to how to stay alert throughout Southern California — in rainy season, fire season or any season.

Understanding National Weather Service terms

Here’s an excerpt from our guide to understanding flood alerts:

• Flood advisories are how the NWS begins to raise the alarm. The goal is to give people enough time to take action.
• Flood watches are your indicators to get prepared to move.
• A flood warning is issued when a hazardous weather event is imminent or already happening. When one is issued for your area, you need to get to higher ground immediately.
• A flash flood warning is issued when a flash flood is coming or in progress. Flash floods are sudden and violent floods that can start within minutes.

Read more: Flash flood warnings? Watches? Here’s what you need to know

Tips for driving in the rain

• Check  weather  and  road conditions along your planned route.
• Slow down.
• Keep a wider-than-usual distance between your vehicle and the one in front.
• Don't drive through standing water — as little as 12 inches of rushing water can carry away most cars, and 2 feet can carry away SUVs and trucks.
• Make sure tires are fully inflated.
• Check windshield wiper blades and replace if necessary.

Read more:  What you should do if you end up driving in a flooded area

Downed tree, power line or flooded road?

Dial 911 in an emergency.

However, if you need to report a flooded road or a downed tree, you can call the following non-emergency numbers:

• L.A. city: Dial 311 for a flooded road or downed tree. Call (800) DIAL-DWP if you see a downed power line.
• L.A. County: (800) 675-HELP
• Ventura County: (805) 384-1500
• Orange County: (714) 955-0200 or visit here .

If you're in L.A. County and need sand bags , you can find some at local fire houses.

Staying safe when the winds are high

• Watch for traffic signals that may be out. Approach those intersections as four-way stops.
• Make sure you have a battery-operated radio and flashlights. Check the batteries to make sure they are fresh. Use flashlights for lighting during a power outage; do not use candles because they may pose a fire hazard.
• If you’re in a vehicle with a fallen power line on it, stay in the vehicle and remain calm until help arrives. It is OK to use your cellphone to call 911. If you must leave the vehicle, exit away from downed power lines and jump from the vehicle, landing with both feet together. You must not touch the vehicle and the ground at the same time. Then proceed away from the vehicle by shuffling and not picking up your feet until you are several yards away. 
• Water and electricity don’t mix. Water is an excellent conductor of electricity. Do not step in or enter any water that a downed power line may be touching.
• Do not use any equipment indoors that is designed for outdoor heating or cooking. Such equipment can emit carbon monoxide and other toxic gases.
• If you use a generator, place it outdoors and plug individual appliances directly into it, using a heavy-duty extension cord. Connecting generators directly to household circuits creates “backfeed,” which is dangerous to repair crews.
• Leave the doors of your refrigerator and freezer closed to keep food as fresh as possible. Place blocks of ice inside to help keep food cold. Check food carefully for signs of spoilage. 
• Check on your neighbors to make sure everyone is safe.

Sign up for emergency alerts

• L.A. City: Notify L.A.
• L.A. County: Ready L.A. County
• Ventura County: Ready Ventura County
• Orange County: AlertOC
• Riverside County: AlertRivCo
• San Bernardino County

How we're reporting on this

LAist science reporter Jacob Margolis is talking to meteorologists, as well as monitoring National Weather Service forecasts and government alerts. Other LAist staffers are monitoring official sources of information as well.

This is a developing story. We fact check everything and rely only on information from credible sources (think fire, police, government officials and reporters on the ground). Sometimes, however, we make mistakes or initial reports turn out to be wrong. In all cases, we strive to bring you the most accurate information in real time and will update this story as new information becomes available.