The MCA does not issue flood or debris-flow warnings. For official watches and warnings follow the National Weather Service and LA City Emergency Management. In any emergency, call 9-1-1.
Why water is a canyon problem
The same terrain that makes the canyon a fire risk makes it a water risk.
Rain that falls anywhere on the canyon walls ends up in the same place: the canyon floor and Mandeville Canyon Road. Steep slopes move water fast, and fast water carries whatever is loose — soil, rock, vegetation, and debris — down with it.
After a fire the risk rises sharply. Burned ground sheds water instead of absorbing it, and a burn scar can produce a damaging debris flow in a storm that would have been unremarkable before the fire. Debris-flow risk stays elevated for several rainy seasons after a burn.
Before the rain
Work done in the dry months is worth more than anything you can do once a storm is on top of you.
Clear your drainage
Clear leaves and debris from gutters, downspouts, area drains, culverts, and the ditch or swale along your frontage. A blocked culvert sends water onto the road — and often into a neighbor's property.
Know where your water goes
Walk your property and find the path water takes when it rains hard. Note where it leaves your lot and where it arrives from uphill. That path is where sandbags, diversion, or drainage work will actually help.
Sandbags and barriers
Get sandbags before the first storm, not during it — supplies go quickly once rain is forecast. Check with LAFD and the City of Los Angeles for current sandbag availability near the canyon. Place them to redirect flow away from doorways, garages, and downhill structures.
Plan for a closed road
A washout, mudslide, or downed tree can close Mandeville Canyon Road with residents on both sides of it. Keep enough food, water, medication, and fuel on hand to sit out a closure, and keep your phone charged.
During a storm
Do not drive through moving water or across a debris-covered roadway. You cannot see whether the road under it has washed out, and it takes very little moving water to carry a vehicle. Turn around and find another way.
If you hear a roar, feel the ground shift, or see mud and rock moving on a slope above you, move away from the drainage and to higher ground immediately — then call 9-1-1. Debris flows arrive faster than you can outrun them downhill.
Report a drainage problem
Blocked culverts, road flooding, slope failures, and washouts.
Rainfall and storm outlook
Disclaimer
This page is general preparedness information for Mandeville Canyon residents. It is decision support only — it is not a notification system, and it is not an engineering assessment of your property. Conditions vary lot by lot; consult a licensed civil or geotechnical engineer for advice specific to your slope, drainage, or structures.
Aware Neighbors, the Mandeville Canyon Association, Westside Coalition, Inc., LAFD, MRCA, and participating partners make no warranty of any kind as to the accuracy or completeness of this information and bear no liability for outcomes based on its use. In any real emergency, call 9-1-1 and follow the instructions of official authorities.
For fire-weather conditions, see Regional fire weather