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FEMA flood zones · Idaho

Lewis County, Idaho Flood Zone Map

3 federal flood & hurricane disasters

FEMA’s digital flood map shows no high- or moderate-risk zones in Lewis County. That can mean the area was never studied in detail or has no digital map, not that it can’t flood; the county floodplain administrator can say which.

Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.

Coastal high risk (V, VE)FloodwayHigh risk (A, AE)Moderate (X, 500-year)Minimal (X)Undetermined (D)

Shaded areas are FEMA’s mapped flood hazard zones in and around Lewis County, Idaho. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.

In their words

2 NOAA storm reports from Lewis County describe what happened, in the words of the forecasters who covered it. Read the Idaho flood stories →

Federal disasters

11 federal disaster declarations since 1964, 3 of them floods, coastal storms or hurricanes.

DisasterBegan
Severe Storm, Flooding, Landslides, And MudslidesApr 14, 2024
Severe Storms, Flooding, Landslides, And MudslidesApr 7, 2019
Clearwater Lawyer Branch Fire ComplexAug 10, 2015
Severe Storms And FloodingJun 2, 2010
Hurricane KatrinaAug 29, 2005
WildfiresJul 27, 2000
Severe Storms And FloodingFeb 6, 1996
Forest FiresAug 30, 1967

Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.

Recorded flood events

4 since 1996: 4 river or area floods.

EventDateDamage
FloodDec 26, 2022$1,000
FloodJun 12, 2022$2,000
FloodApr 9, 2019$100,000
FloodApr 2, 2011—

— = no damage estimate in the record. Source: NOAA Storm Events Database.

From the storm reports

Flood · Dec 26, 2022. Rain amounts near an inch and melting snow caused flooding issues in the area including Paradise Creek in Moscow.

Flood · Jun 12, 2022. Another trough system brought a round of slow moving stratiform slow moving showers. With the abundant amount of precipitation from earlier in the month, the streams and creeks were already near bank full. The additional 1 inch of precipitation starting to create problems for low lying areas in the Southeast WA and Lower ID Panhandle.

Flood · Apr 9, 2019. Beginning on April 6th and continuing through April 10th a series of Pacific atmospheric rivers were directed into Oregon, southeast Washington and central Idaho saturating the ground with heavy rainfall. During this 4 day period the COOP station at Kamiah reported 1.86 inches of rain, Elk River reported 2.94 inches of rain, Moscow 3.44 inches, Nez Perce 2.05 inches, Potlatch 2.46 inches, Dworshack Fish Hatchery 3…

Flood · Apr 2, 2011. A stationary trough of low pressure off the Pacific Northwest Coast steered a deep fetch of subtropical moisture into the Idaho Panhandle which persisted from the end of March through April 7th bringing several rounds of heavy rain. Mild temperatures and breezy winds accompanying the subtropical moisture feed resulted in excessive mid-elevation snowmelt. The combination of heavy rainfall and excessive runoff resu…

National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.

The zones you’ll see on the map

Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.

Cross-section of a river floodplainDiagram: a river valley. The floodway is the channel and the land beside it; the 1%-annual-chance flood surface (the base flood elevation) covers the valley floor as zone A or AE; a narrow band higher up is shaded X, the 0.2% floodplain; higher ground is X.0.2% CHANCE A YEAR (500-YEAR)BASE FLOOD ELEVATION · 1% A YEARXAEFloodwayAEX
  1. A / AE Inside the 1%-a-year floodplain: about a 26% chance of flooding over a 30-year mortgage. AE has a mapped base flood elevation; plain A does not.
  2. Floodway The channel and the land beside it that has to be kept clear enough to carry the flood. Building here is tightly limited.
  3. X shaded The 0.2% (500-year) floodplain, plus some levee-protected and very shallow flood areas.
  4. X Outside both lines. No federal requirement to insure, which is not the same as no risk.

Every flood zone code explained →

Flood insurance in Lewis County

If a building in Lewis County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.

Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.