This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Residents of Trabuco Canyon are being warned of the risk for mud and debris flow in areas left scorched by the 23,000-acre Holy Fire, as heavy rainfall stemming from Hurricane Rosa is expected to hit the area in the coming days, Orange County officials said Friday.

Thunderstorms are expected to scatter through the area burned by the wildfire — which spread through Cleveland National Forest and the Trabuco Canyon area last month. The heavy rain is expected to fall over a three-day period spanning from late Sunday through Wednesday, county officials said.

The rainfall is the result of Hurricane Rosa, which forecasters said is expected to weaken to a tropical storm before it makes its way toward Southern California with another storm expected to follow it.

Parts of Orange County that were left scorched by the Holy Fire, which burned thousands of acres after breaking out on Aug. 6, are vulnerable to mud and debris flow that could be triggered by the heavy rain, official said.

That could mean “fast-moving landslides” that happen with “little or no warning,” county officials said in a news release.

More than an inch of rain is expected from Sunday through Wednesday, forecasters said.

Thousands of people faced mandatory evacuations last month due to the wildfire as U.S. Forest officials later announced 51-year-old Forrest Gordon Clark was arrested on suspicion of starting the blaze.

It had quickly exploded in size as it was fueled by heavy brush and steep terrain and traveled through Orange and Riverside counties — hitting upper parts of Trabuco Canyon and Holy Jim areas, fire officials said.

County officials said residents can prepare for the risk of mud flow by doing the following:

  • Make plans for leaving in case roads are closed due to flooding.
  • Find higher ground if there are debris and mud flows.
  • Obtain sandbags to protect homes and property from flooding.
  • Leave during voluntary evacuations, if possible, rather than later during mandatory evacuations.
  • Find and use alternate routes in case road closures happen.
  • Stay out of flooding waters as the depth of mud and water can be difficult to measure with the naked eye.
  • Have an emergency plan and disaster kit ready.