Flood Information

Flooding is a temporary overflow of water onto land that is normally dry. Flooding can happen during heavy rains, when rivers overflow, when ocean waves come on the shore, when snow melts too fast, or when dams or levees break. Flooding may be only a few inches of water, or it may cover a house to the rooftop. Floods that happen very quickly are called flash floods. Floods are the most common natural disaster in the United States.  

Failing to evacuate flooded areas or entering flood waters can lead to injury or death. 
Floods may: 
  • Result from rain, snow, coastal storms, storm surges and overflows of dams and other water systems. 
  • Develop slowly or quickly. Flash floods can come with no warning.   
  • Cause outages, disrupt transportation, damage buildings and create landslides.

Know Your Alerts and Warnings

Flash Flood - A flood that can happen in a few minutes or hours of heavy rainfall, dam/levee failure, or drains overflowing. 
Flood Watch - A message that flooding is possible. 
Flood Warning - A message that flooding will happen soon (if it hasn’t already).  
Levee/Dam - A structure to contain or prevent water from overflowing and flooding an area. 

If your area is under a flood warning:
  • Find safe shelter right away.
  • Do not walk, swim or drive through flood waters. Turn Around, Don’t Drown!
  • Remember, just six inches of moving water can knock you down, and one foot of moving water can sweep your vehicle away.
  • Stay off bridges over fast-moving water.
  • Depending on the type of flooding:
    • Evacuate if told to do so.
    • Move to higher ground or a higher floor.
    • Stay where you are.

Steps Before the Flood

  • Make an emergency communications plan for your household.
    • Emergency Communications Plan
      • Items to include: evacuation routes, meeting places, shelter locations, insurance policy and information, medical and veterinarian information, household needs, and disaster supply checklist.   
  •  Planning is vital to making sure that you can evacuate quickly and safely. 
  •  Build a disaster supply kit for all members in your household, including your pets. 
  • Document your belongings.
    • Create a list or video of your personal items and valuables.
    • Gather personal documents - passports, social security cards, medications, property leases, deeds, home and auto titles, and financial documents.
  • Know the flood risk for your area.

Steps to Protect Your Property:

  • Elevate the furnace, water heater and electric panel in your home if you live in a high flood risk area. 
  • Consider installing "check valves" to prevent flood water from backing up into the drains of your home. 
  • If feasible, construct barriers to stop floodwater from entering the building and seal walls in basements with waterproofing compounds. 
  • Clear leaves and debris on your property that leads to stormwater conveyance systems such as streets, streams or creeks. This includes removing snow and ice berms to help water pass through properly.  
  • Clean out gutters and downspouts on your property. 
  • Secure outdoor furniture, fences, sheds, temporary construction structures, canopies, and other objects.  
  • Anchor fuel tanks and external utility links.  
  • Unplug appliances not in use.

Staying Safe During a Flood

  • Pay attention to authorities and safety officials. If there is any possibility of a flash flood, move to higher ground or find shelter.
  • Evacuate immediately, when asked to be local officials. Never drive around barricades. Local responders use them to safely direct traffic out of flooded areas.
  • Contact your healthcare provider If you are sick and need medical attention. Wait for further care instructions and shelter in place, if possible. If you are experiencing a medical emergency, call 9-1-1.
  • Listen to EAS, NOAA Weather Radio or local alerting systems for current emergency information and instructions regarding flooding.
  • Do not walk, swim or drive through flood waters. Even six inches of moving water can knock you off your feet. Turn Around. Don’t Drown!
  • Stay off bridges over fast-moving water. Fast-moving water can wash bridges away without warning.
  • Stay inside your car if it is trapped in rapidly moving water. Get on the roof if water is rising inside the car.
  • Get to the highest level if trapped in a building. Only get on the roof if necessary and once there signal for help. Do not climb into a closed attic to avoid getting trapped by rising floodwater.

Staying Safe After a Flood

  • Pay attention to authorities for information and instructions. Return home only when authorities say it is safe.
  • Avoid driving except in emergencies.
  • Wear heavy work gloves, protective clothing and boots during clean up and use appropriate face coverings or masks if cleaning mold or other debris. 
  • People with asthma and other lung conditions and/or immune suppression should not enter buildings with indoor water leaks or mold growth that can be seen or smelled. Children should not take part in disaster cleanup work.
  • Be aware that snakes and other animals may be in your house.
  • Be aware of the risk of electrocution. Do not touch electrical equipment if it is wet or if you are standing in water. Turn off the electricity to prevent electric shock if it is safe to do so.
  • Stay away from and avoid wading in floodwater, which can be contaminated and contain dangerous debris and substances. Underground or downed power lines can also electrically charge the water.
  • Use a generator or other gasoline-powered machinery ONLY outdoors and away from windows.
  • Stay away from moving water. It can knock you off your feet.
  • Stay out of the way of emergency workers so they can do their job easily.
  • Know that it’s normal to feel anxious or stressed out. Everyone reacts differently to stressful situations.

Snowmelt Flooding

What is a snowmelt flood? A flood is considered a snowmelt flood when melting snow is a major source of the water involved. Unlike rainfall, which reaches the soil almost immediately, snow stores the water for some time until it melts, delaying the arrival of water in the soil for days, weeks, or even months. Once it does reach the soil, the water either soaks into the ground or runs off. If more water runs off than soaks in, flooding occurs. 

How common are snowmelt floods? Are they severe? Snowmelt flooding typically occurs every year in the northern United States, with most snowmelt events being minor and localized. Eight of the most significant floods of the 20th century (in terms of area affected, property damage, and deaths) were related to snowmelt. 

What causes snowmelt flooding? High soil moisture conditions before snowmelt, frozen ground, heavy snow cover, widespread heavy rain during the melt period, and rapid snowmelt (unseasonably warm temperatures, high humidity, rainfall, etc.).

Ice Jams

What are ice jams? Ice jams are a buildup of water behind ice on a body of water. Ice jam floods can occur because of snowmelt flooding adding to the amount of water in the river or lake. 

How quickly do ice jam floods occur? The rates of water level rise can vary from feet per minute to feet per hour during ice jam flooding. This means some communities have as little as one hour before flooding occurs after ice breaks up to many hours. 

What kind of problems do ice jams cause? Ice jams are responsible for loss of life, approximately $125 billion in damages annually, and disrupt commercial navigation and hydropower operations. Ice jams also scour streambeds and may adversely affect fish and wildlife.

Debris Flow

What is debris flow? Debris flow is caused by rainfall on burned hill slopes. Just a small amount of rainfall on a burned area can lead to these hazards. 

Why should I be worried about debris flows? The powerful force of rushing water, soil, and rock, both within the burned area and downstream, can destroy culverts, bridges, roadways, and structures, and can result in injury or death. 

What is being done to prevent debris flows or at least mitigate the impact? The U.S. Geological Survey and the National Weather Service are working together to develop improved landslide hazard assessments, better post-disaster response, and public information and outreach.

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Archive Information on 2023 Flood Events

Content included:

  • Spring Thaw
  • March Atmospheric River 
  • Local Emergency Declarations
  • Presidential Declaration 
Click Here for Archived Information