© 2024 Boise State Public Radio
NPR in Idaho
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Here's how to prepare for flooding in Idaho

Rushing water in the Big Wood River through a canyon
National Weather Service
Rushing water in the Big Wood River during the 2006 flood year.

Floods are some of the most common, costly and damaging disasters in the U.S. Floods happen when water overflows onto normally-dry land. Heavy rainfall, snow melt, storm surges and dam failures can all lead to flooding. The overflowing water can develop slowly or very fast; flash floods can come with barely any warning at all.

Know your risk

Flood maps show how likely it is to flood in your area. High-risk areas within a 100-year floodplain have a 1% annual chance of experiencing flooding. That translates to a 26% chance of your area flooding over the course of a 30-year mortgage.

You can see if you live in an area prone to flooding by entering your address into the FEMA Flood Map Service Center.

FEMA works with local officials to develop flood risk maps. Still, they’re not perfect. Sometimes they’re outdated and don’t reflect the on-the-ground experience of the latest flood. Moreover, there’s no such thing as a “no-risk” area. You can call your city or county to find out if you live in a floodplain.

The Idaho Office of Emergency Management’s 2023 hazard mitigation plan says 60,650 people in the state live in a 100-year floodplain. And, according to FEMA’s National Risk Index, 17 of Idaho’s 44 counties are at risk of riverine flooding. The counties with the highest risk, according to a number of factors, are listed in the table below.

Flood risk by Idaho county
Idaho Office of Emergency Management

Purchase flood insurance

Most homeowners insurance does not cover flood damage. Experts recommend purchasing it whether you’re in a high-risk zone or not, as even just an inch of water can cause up to $25,000 in damage to a home. And, it helps to plan ahead. It’s typical for policies to have a 30-day waiting period.

On average, about 40% of National Flood Insurance Program (NFIP) claims come from outside high-risk areas. In Idaho, about 25% of claims paid are in zones at low or medium risk of flooding.

The vast majority of Idaho communities participate in the NFIP, which provides flood insurance to property owners, renters and businesses. In turn, participating communities are required to adopt and enforce floodplain management regulations.

To find flood insurance providers, visit FloodSmart.gov/flood-insurance-provider. If you’re a renter, you can also get flood insurance that protects your belongings.

Sign up for emergency alerts

Every county in Idaho has access to the Integrated Public Alert and Warning System – FEMA’s national system, which allows local authorities to provide emergency information to the public via mobile phones, as well as radio and television.

In addition, the Emergency Alert System is a national public warning system that can interrupt radio and television to broadcast emergency information. The president can use the system to address the country within 10 minutes during a national emergency, and local authorities can use the system to share imminent weather information, threats and AMBER alerts targeted to specific areas.

Finally, several Idaho counties have their own emergency alert systems you can sign up for:

Take stock of your valuables

  • Take photos of important household items as having these images can be helpful when filing insurance claims
  • Save copies of important documents like birth certificates, passports and medical records
  • Make a plan to evacuate 

Responding to floods

  • Don’t walk, swim or drive through flood waters – just six inches of water can knock you down and one foot of water can move your car
  • Find shelter and higher ground, but stay off bridges 
  • Evacuate if you’re told to do so
  • Stay informed by tuning into NOAA Weather Radio

You make stories like this possible.

The biggest portion of Boise State Public Radio's funding comes from readers like you who value fact-based journalism and trustworthy information.

Your donation today helps make our local reporting free for our entire community.