Much of Southern California is expected to get at least an inch of rain from Monday night to Tuesday morning. That’s more than enough to cause debris flows, according to Chief Sam DiGiovanna of the Verdugo Fire Academy. The Pacific Palisades, Malibu and Altadena neighborhoods, which already experienced so much destruction from the wildfires this year, are especially vulnerable due to a lack of vegetation or steep slopes.
Why are burn scar areas more vulnerable to mudslides?
We have what’s called hydrophobic planning: When the vegetation is completely stripped from the hillsides, the water runs right off the hillside area, collects a lot of the water in the mud, and it can lead to mudflow and erosion problems. Without that vegetation on the hillsides, it’s going to quickly flow right through canyons, channels and streets.
Forecasts predict an inch of rain in some areas. Is that enough to cause a mudslide?
Absolutely. It doesn’t take a lot of rain, especially in the burn scar areas. Up to a quarter inch or half inch of rain in a short amount of time can cause a mudslide.
What are some mudflow warning signs homeowners should be looking for?
Start by finding cracks in hillside retaining walls. That’s a good sign of water that’s seeping in areas around your home that you don’t normally see. Cracks on the interior and exterior of the walls of your home, also door jambs or windows that are stuck, sticky or hard to open. Those are good signs that the earth is moving.
What should you do if you get caught in the middle of a mudflow?
If you’re outside, move uphill to higher ground as quickly as possible. Mudflows travel downhill rapidly and can quickly cover everything in their path. Avoid riverbeds and water channels. These are natural pathways for debris flows. Don’t try to outrun a mudflow. Instead, take shelter behind a large, stable object, like a boulder or sturdy wall. This will help deflect the debris and the mud flow.
Is it better to stay indoors or outdoors during a mudslide?
It’s best to stay indoors unless authorities ask you to evacuate. Move to higher floors in your home, especially if you’re downhill or near a channel. Avoid downhill-facing walls and windows as mudflow can breach them. If you hear rumbling or see debris approaching, like an earthquake, duck, cover and hold, and protect your head.
Source: NBC Los Angeles