CALIFORNIA, Md. — Slow-moving summer thunderstorms are a familiar part of life across Maryland. From the Chesapeake Bay region to communities in Southern Maryland, Central Maryland and the Washington area, heavy rain can fall in a short period of time and quickly overwhelm streets, creeks and low-lying areas.
Maryland flash flood safety starts with understanding that flooding can develop much faster than many people expect. Even neighborhoods that rarely experience standing water can see dangerous conditions when storms repeatedly move over the same location or produce intense rainfall. Flooding is the most frequent severe weather event and the costliest natural disaster in the country, according to Montgomery County, Maryland’s Department of Environmental Protection.
Preparing before severe weather arrives can help families make better decisions and reduce the risk of injury or property damage.
Why Flash Flooding Can Happen Quickly
Flash flooding develops when rain falls faster than the ground, storm drains and waterways can handle it. Urban areas with large amounts of pavement may experience flooding because water has fewer places to soak into the ground. Rural communities can also see creeks, streams and drainage ditches rise rapidly.
In Maryland, flash flooding can affect coastal communities, inland neighborhoods and areas near rivers or small streams. Roads that appear safe during normal weather may become hazardous after a prolonged thunderstorm. Residents can check current conditions on the USGS National Water Dashboard Status Map, a real-time monitoring tool, as a resource for tracking flood risk.
Conditions can also change within minutes. A road that was dry earlier in the afternoon may become flooded before the evening commute.
Build A Family Flood Plan
Every household should have a simple emergency plan before severe weather develops. The Maryland Department of Emergency Management (MDEM) recommends building an emergency kit, creating a family communications plan, and contacting local emergency managers to find out whether your home sits in a floodplain.
Talk with everyone in the home about where to go if flooding threatens your neighborhood. Identify more than one way to leave your area in case a familiar road becomes impassable.
Choose an out-of-town contact who can serve as a communication point if family members become separated. Make sure children know how to reach trusted adults and understand basic emergency procedures.
If someone in your household depends on medical equipment, mobility devices or prescription medications, include those needs in your planning. Pet owners should also prepare supplies and transportation plans for animals.
It’s also worth reviewing your insurance coverage well before a storm threatens: MDEM notes that standard homeowners and renters policies typically do not cover flood damage, and points residents to the National Flood Insurance Program to check available coverage.
Assemble An Emergency Kit
A basic emergency kit can make it easier to manage if flooding interrupts power or limits travel.
Include items such as:
- Drinking water and shelf-stable food.
- Flashlights and extra batteries.
- A battery-powered or hand-crank weather radio if available.
- First-aid supplies.
- Prescription medications and essential medical items.
- Phone chargers, including portable battery packs.
- Copies of important documents stored in waterproof containers or digitally backed up.
- Supplies for infants, older adults and pets as needed.
Store the kit in an easily accessible location and review it before each summer storm season.
Stay Informed During Severe Weather
Weather conditions can change quickly during slow-moving thunderstorms. Monitor forecasts from the National Weather Service, which covers the Baltimore-Washington region, and pay attention to flood watches, flood warnings and emergency alerts.
Wireless emergency alerts on smartphones, local news coverage and official weather information can provide timely updates when flooding develops. Many Maryland counties, including Montgomery County, also let residents subscribe directly to local emergency notifications and check flood-risk mapping tools maintained by county government.
Do not assume a storm has ended simply because rainfall briefly slows. Water levels may continue rising after heavy rain has stopped, especially downstream.
Never Drive Through Flooded Roads
One of the most important parts of Maryland flash flood safety is avoiding flooded roadways. The National Weather Service’s long-running “Turn Around Don’t Drown” campaign puts the danger in concrete terms: just 6 inches of fast-moving water can knock over an adult, 12 inches can carry away most cars, and 2 feet of rushing water can sweep away SUVs and trucks. More than half of all flood-related drownings happen when a vehicle is driven into hazardous floodwater, according to the National Weather Service, and flooding causes more deaths nationally than any other thunderstorm-related hazard.
Water may hide washed-out pavement, debris or strong currents. It is often impossible to judge a road’s condition by looking at the surface, and the National Weather Service specifically warns against driving around barriers blocking a flooded road, since the pavement underneath may have already washed out.
If you encounter water covering the roadway, turn around and choose another route. Waiting a few minutes or taking a longer path is far safer than attempting to cross floodwaters.
Drivers should also avoid parking in low-lying areas when heavy rain is expected, since rising water can damage vehicles in a short amount of time.
Know What To Do After Flooding
Floodwater may contain contaminants or hide hazards beneath the surface. The Maryland Department of Emergency Management warns that floodwater can carry oil, gasoline or sewage contamination, so avoid walking through standing water whenever possible and clean and disinfect anything that was exposed, since residual mud may contain harmful substances.
If your home has been flooded, use caution before re-entering. Watch for structural damage, electrical hazards and other dangers. Follow guidance from local officials before returning to affected areas.
Photograph damage for insurance purposes when it is safe to do so. Contact your insurance provider to learn about the claims process and ask what documentation may be needed.
Discard food or medications that may have been exposed to floodwater unless officials indicate they remain safe to use.
Frequently Asked Questions
What is the safest thing to do during a flash flood?
Move to higher ground if flooding threatens your area, follow official emergency information from sources such as the National Weather Service and the Maryland Department of Emergency Management, and avoid walking or driving through floodwaters.
Should I drive through a flooded road if the water looks shallow?
No. The National Weather Service says just 12 inches of moving water can carry away most cars, and floodwater may hide washed-out pavement, debris or strong currents. Turn around and use another route.
What should be included in a family flood emergency kit?
Include water, nonperishable food, flashlights, batteries, first-aid supplies, medications, phone chargers, important documents and supplies for pets or family members with specific needs, as recommended by the Maryland Department of Emergency Management.
Can flash flooding happen outside of coastal areas in Maryland?
Yes. Flash flooding can occur in cities, suburbs and rural communities wherever heavy rainfall overwhelms drainage systems, streams or low-lying areas. Montgomery County’s government notes that flooding is the most frequent type of severe weather event nationally.
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