Know at-risk areas - mountain edges, steep slopes or drainage channels

After the fires came the floods. But in parts of southern California, there was a third item on their menu of natural calamities: mudslides.

Last June, a severe lightning storm over one weekend triggered over 800 wildfires that took weeks to put out, and some of them are still burning. Thousands of square miles have been blackened by these wildfires.

Over the last weekend, heavy thunderstorms again struck California bringing lots of rain. This triggered mudslides in areas that were scarred in last year’s wildfires. The mudslides were 300 yards wide in some places and up to 3 feet deep.

The mudslides blocked Highway 395 causing a full closure for several hours, until a single lane was opened. The highway links the Inland Empire area and Reno, Nevada.

The mud stopped just a half mile short of the Los Angeles Aqueduct, the most important source of water for Los Angeles. Luckily, there were no injuries although at least 50 homes were damaged.

The National Weather Service has warned that when heavy downpours come, there will be increased likelihood for flash floods accompanied by mudslides and flows of debris. The NWS said the places particularly vulnerable to floods and mudslides will be those areas devastated by fires in the last two years, because there still is not enough vegetation to absorb the rainfall or to stop the water/mud flows.

Residents in areas scorched by wildfires this year should remember this warning next summer when the rains come. The fires they had this year increase the likelihood of flash floods and mudslides occurring next year. They must prepare for that accordingly.

Safety Tips for Mudslide Preparedness:

Before a Mudslide/Debris Flow

* Have your property undergo a ground assessment. If you can avoid it, do not locate your home near mountain edges, steep slopes or drainage channels.

* Gather information from all possible sources (e.g. local government, university geology departments, and state geological surveys) on landslides in your area and ask for a reliable referral for a professional site analysis on your property.

* Make sure only flexible fittings are used for gas and water pipes, to avoid leaks.

* Plant vegetation on slopes to provide ground cover.

* If necessary, have retaining or deflection walls and channels built to direct mudflows. Caution: If your walls cause debris flow to land on the property of your neighbor, you could be liable for damages.

During a Mudslide/Debris Flow

* Be alert and stay vigilant. Most fatalities from mudslides happen when people are caught sleeping.  Be alert for NWS warnings of heavy rainfall. Short but intense bursts of rain are especially dangerous.

* If you live in an at-risk area, consider the possibility of leaving if and when conditions are safe. Note that driving conditions are hazardous during intense storms. If you cannot leave home, move to an elevated place — a second story, if available.

* Listen for sounds associated with moving debris (e.g. cracking tree limbs). Mudslides move quickly and with little warning.

* Be watchful when driving, especially near embankments. Collapsed pavement, fallen rocks, and mud are signs of possible debris flows.