What to Do Before the First Major Rain

The short version

• Clear gutters, downspouts, and roadside culverts before the rain so the first flush doesn't back up.
• Prep for outages now: water, lights, chargers, and a plan for anyone who depends on power.
• If you live below or near a CZU burn scar, know your evacuation zone and leave promptly if a warning is issued. This is the one that can't wait.
• Sign up for the county's emergency notifications and PG&E outage alerts.
• Refresh your storm kit and keep the car at least half full through the season.

The first real storm of the season is the one that catches people out. After a dry summer, the drains are packed with needles, the ground sheds a sudden downpour instead of soaking it up, the roads run slick with the summer's oil, and on the hillsides the CZU fire burned, bare ground can send debris flows down fast. Most of the prep is cheap and takes an afternoon, and it goes a lot easier on a dry weekend than during the first downpour. Here's the Boulder Creek checklist. For live forecasts, watch the National Weather Service and our Mountain Status page.

Clear the water's path

Water finds the low point, and in the mountains that's often your foundation, driveway, or road. Before the rain:

• Gutters and downspouts: clear out summer needles and leaves, and make sure downspouts carry water away from the house.
• Culverts and roadside drains: clear the culverts and drains around your property so the first flush doesn't back up and flood.
• The lay of the land: look at where water will actually go across your property, and move anything that will wash into a drain.

Get ready for outages

The first storms bring down limbs and knock out power. Get ahead of it rather than scrambling in the dark: water, lights, chargers, and a plan for anyone who depends on power.

Our power-outage preparation guide walks through it, and you can sign up for PG&E outage alerts now.

Know the burn-scar risk

This is the serious one. Hillsides burned in the 2020 CZU fire shed water fast and can produce debris flows, fast-moving slurries of mud, rock, and trees, during intense rain.

The National Weather Service issues Flash Flood Warnings for burn areas, and those warnings often name the debris-flow risk directly. They can come with very little lead time. If you live below or near a burn scar, know your evacuation zone now, take those warnings seriously, and don't wait to leave if one is issued for your area.

Stock up and secure

• Storm kit: refresh food, water, flashlights, batteries, and a battery or hand-crank radio.
• Loose items: secure or store anything outdoors that blows around in wind.
• Roof and tarps: check them while it's still dry.
• The car: fuel up and keep it at least half full through the season.

Sign up for alerts

The single best thing you can do is make sure the warnings reach you. Register for the county's emergency notifications and PG&E alerts before the first storm, and bookmark Mountain Status for live conditions.

Frequently asked questions

Why is the first big rain such a problem here?

After a dry summer, drains are clogged, the ground sheds sudden rain instead of soaking it up, roads are slick, and burned hillsides can produce debris flows. A little prep on a dry day prevents most of the trouble.

What's the debris-flow risk in Boulder Creek?

Hillsides burned in the 2020 CZU fire can produce fast-moving debris flows during intense rain. The National Weather Service warns for these with little notice. Know your evacuation zone and leave promptly if a warning is issued.

What should I do first?

Clear your gutters and culverts, prep for a power outage, sign up for alerts, and if you're near a burn scar, know your evacuation zone. Do it on a dry weekend, not during the storm.

Last reviewed July 20, 2026. This is a checklist, not a forecast, and it links to official sources from the National Weather Service and PG&E. For live conditions, see Mountain Status and the National Weather Service. In an emergency, call 911.

Storm prep is one part of a longer rhythm. For the rest of the year's mountain-home upkeep, see the Boulder Creek home maintenance calendar, and the Residents guide for utilities, outage planning, and county contacts in one place.