December 10, 2021
A moderately strong frontal system with a tap of very moist air, also known as an Atmospheric River (AR), is expected to bring moderate to heavy rain to the region Sunday and continuing through Tuesday. Heavy rain will lead to rapid rises of area rivers, streams, and creeks. Flooding may result if the system stalls over an area for a prolonged period of time as models project or due to blocked culverts, drainages, and storm drains. However, as with all ARs, where, when, or if they stall is difficult to pin down. This system will result in an increased risk of mudslides and debris flow over wildfire burn areas, as well as localized ponding of water in low-lying or poorly drained areas. 1 to 3 inches of precipitation is forecast for most urban and lower elevation areas, potentially less in rain shadowed valleys. 3 to 6 inches of rain is projected over the coastal ranges and elevated terrain.
Hazardous Weather Conditions
Thank you to all our public safety personnel (Fire, Police, Public Works, and agency partners) for keeping us safe.
For additional resources, see the links below:
Check on power outages impacting our area
Marin County Emergency Portal
Updates: Mill Valley PD Twitter
Special Advisory to Residents in Low-Lying Areas
Mill Valley has had a history of experiencing localized flooding in low-lying areas. If you live in an area that has a history of flooding, it is highly recommended that you be proactive now and stay alert.
- Monitor the local creek and tide levels.
- Consider moving personal belongings to higher ground, including vehicles.
- Avoid walking in flood waters as this could pose a threat of injury or death.
- If present, avoid down power lines.
- If conditions worsen, the Fire Department recommends you shelter in place.
PREPARE FOR THE STORM
- Secure garbage cans, lawn furniture or anything that could become airborne and cause damage.
- Clean out gutters, storm drains, etc. (keeping drains clear of trash, leaves and branches) so rainwaters can easily flow, reducing possible flooding and ponding.
- Commuters who travel in areas with a history of flooding are advised to monitor high tides. Check traffic conditions prior to your trip to anticipate congestion. Road closures are often posted by the Mill Valley Police Department on Twitter.
- Please be advised to keep out of creeks and waterways during the storm.
- Sign up for alerts and warnings.
Power Outages/Downed Power Lines
Residents are advised of possible downed trees and power lines. Report downed power lines by calling 9-1-1 and PGE at 1-800-743-5002. Stay away from the downed powerlines and assume they are energized and dangerous.
- Check to make sure you have batteries, fully charged back-up battery packs for your devices, and a battery powered radio.
- Recharge your laptop computer, cell phone, and other mobile devices as a precaution against a power outage.
- Have flashlights with extra batteries for every household member.
- Freeze water bottles or bags of water for food storage if the power goes out.
- Have enough nonperishable food and water.
- Make sure you can open your garage door if the power goes out.
If the power goes out:
If you see a downed power line call 911 immediately. For more safety information about downed power lines visit PG&E's website here.
Traffic & Road Closures
Flooding or fallen trees may cause traffic back-ups and road closures. Check our Road Closures and Traffic page for updates.
Drive with Caution:
- When driving in the rain, use extra caution and always have your headlights on. Remember, if you turn on your windshield wipers, turn on your headlights.
- Please obey the speed limits and follow other traffic at a safe distance.
- If traffic signals are out or flashing red, come to a full stop at every intersection, and proceed as you would at a four-way stop.
Stock up on Sandbags
We urge residents to take preparedness measures by seeking sand and sandbags should they need them. Watch a video on how to fill and place sandbags.
Sand and bags can be purchased at local hardware stores. Sand and sandbags may also be located at the following locations:*
*These locations have limited stockpiles of sand and sandbags for emergency use during the rainy season. To use these stockpiles, you must supply your own labor, shovels and support.
Please note that the safety of Mill Valley citizens is the first priority of City work crews, and that replenishing the sand pile and bags may become a lower priority during a storm event. If you have questions or comments please call Department of Public Works at 388-4033 or the Fire Department at 389-4130.
Please also be aware that precipitation can increase the potential for mudslides on steeper terrain. If you see significant runoff on a slope that is not typically used for drainage, it could be due to a blockage or diversion of water from its regular course somewhere upstream. Please report these instances to Public Works at (415) 384-4800. If you feel that the situation constitutes an emergency, please call 9-1-1.
High tides, combined with high run-off sometimes leads to flooding on lower Miller Avenue and Camino Alto, as well as the Redwood Hwy Frontage Road. Please click here for High Tide information.
How to stay informed during winter storms?
Sign up for alerts and warnings. We will post regular updates to the www.cityofmillvalley.org website.
Businesses Preparation Resources
Preparing your business is important - visit the Ready Marin "Ready Business Program" website to learn more.