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A snow covered peak of the North Cascades above evergreens and a small lake

Where the Nooksack floods

Whatcom County's flood problem is mostly one river. Of the county's 1,211 federal flood insurance claims, 59% come from three small towns in the Nooksack lowlands. Here is the record, from federal river gauges and flood insurance data.

Updated October 29, 2026 ยท Sources listed at the end

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On this page
  1. How a Nooksack flood happens
  2. The biggest floods at Ferndale
  3. Flood claims by ZIP code
  4. If you live in the valley

How a Nooksack flood happens

The river drains Mount Baker and the North Cascades. The big floods come in late fall and winter, when an atmospheric river brings warm, heavy rain that falls on snow up high. Of the 77 annual peaks on record at Ferndale, 62 came between October and January. Near Everson the river can spill north over low ground toward Sumas and into Canada's Sumas Prairie, which is what happened in November 2021.

Highest flow each water year, Nooksack River at Ferndale (cubic feet per second)

1945: 41,600 cfs19451949: 27,500 cfs1951: 55,000 cfs1952: 18,300 cfs1953: 19,300 cfs1953: 18,500 cfs1954: 20,700 cfs1955: 35,000 cfs1956: 23,000 cfs1958: 18,300 cfs1959: 30,200 cfs19591959: 22,000 cfs1961: 30,800 cfs1962: 18,800 cfs1962: 26,000 cfs1963: 23,300 cfs1965: 20,000 cfs1965: 17,500 cfs1966: 21,400 cfs1967: 23,900 cfs1969: 28,100 cfs19691969: 17,300 cfs1971: 38,100 cfs1972: 24,800 cfs1972: 24,800 cfs1974: 21,800 cfs1974: 20,800 cfs1975: 46,700 cfs1977: 20,600 cfs1977: 23,900 cfs1978: 18,800 cfs19781979: 36,400 cfs1980: 29,700 cfs1982: 27,200 cfs1983: 34,200 cfs1984: 41,500 cfs1985: 16,300 cfs1986: 29,900 cfs1986: 36,000 cfs1988: 17,700 cfs1988: 21,000 cfs19881989: 47,800 cfs1990: 57,000 cfs57,0001992: 18,100 cfs1993: 19,000 cfs1994: 18,500 cfs1994: 21,700 cfs1995: 47,200 cfs1997: 38,100 cfs1997: 17,600 cfs1998: 24,600 cfs19981999: 22,200 cfs2000: 14,300 cfs2002: 30,300 cfs2003: 20,100 cfs2003: 39,900 cfs2004: 42,300 cfs2006: 19,500 cfs2006: 38,100 cfs2007: 21,100 cfs2009: 51,700 cfs20092009: 22,900 cfs2010: 38,300 cfs2012: 18,900 cfs2012: 20,300 cfs2014: 21,200 cfs2014: 23,600 cfs2015: 27,000 cfs2017: 20,500 cfs2017: 26,500 cfs2018: 21,300 cfs20182020: 36,600 cfs2021: 18,300 cfs18,3002021: 56,300 cfs56,3002022: 19,700 cfs2024: 24,300 cfs2024: 18,200 cfs20241991-2020 typical peak: 22,200
Source: USGS peak streamflow, station 12213100, 1945 to 2024. Water year 2026 (the December 2025 flood) is not in the published peak file yet; its highest daily mean flow was 34,200 cfs on December 11, 2025 (provisional).

The biggest floods at Ferndale

The two largest peak flows in the USGS record came 31 years apart. November 10, 1990 brought 57,000 cubic feet per second. November 16, 2021 brought 56,300. In 2021 the gauge reached 23.89 feet, above the National Weather Service major flood stage of 23 feet. The typical annual peak over 1991 to 2020 was about 22,200 cubic feet per second, so 2021 carried more than twice a normal year's high water.

December 2025 was the next one. USGS provisional data show a daily mean flow of 34,200 cubic feet per second on December 11, 2025; the instantaneous peak for the event isn't in the published record yet. Nine homes in Ferndale near VanderYacht Park took on water, about 150 homes in the city of Nooksack saw flood impacts, and 412 Sumas households had asked for recovery help by December 18 (Cascadia Daily News).

Flood claims by ZIP code

Federal flood insurance claims show where the water reaches houses. Sumas (98295) leads with 348 claims on record, then Everson (98247) with 294 and Ferndale (98248) with 166. Most of Bellingham proper has very few: the south and central ZIP, 98225, has 18. Two months account for most of the county's flood payments: November 2021 (326 claims, $22.5 million paid) and December 2025 (297 claims, $21.6 million paid so far).

Aerial view of brown floodwater spreading across flat farm fields
Floodwater on farm fields. The Nooksack lowlands around Everson and Sumas flooded in 2021 and again in 2025. Photo: Aivars Vilks / Unsplash

If you live in the valley

  • Know the gauge. The NWS flood categories at Ferndale are action 15 feet, minor 18, moderate 20.5 and major 23.
  • Buy flood insurance before the season, not during a forecast: NFIP policies start 30 days after purchase.
  • Keep a list and photos of what is in the house, stored somewhere other than the house.
  • After the water drops, treat everything it touched as contaminated. Flood cleanup.

Questions Whatcom County homeowners ask

Which Whatcom County towns flood the most?

The Nooksack lowlands. Sumas and Everson have the most federal flood insurance claims by ZIP code, Nooksack is close behind, and Ferndale follows. The same towns took the worst of both the November 2021 and December 2025 floods. Most of Bellingham proper is above the floodplain, so in town the water usually comes from inside.

Does homeowners insurance cover a river flood?

No. The Washington Insurance Commissioner says a typical home policy does not cover flood damage. You need a flood policy, through the NFIP or a private insurer, and an NFIP policy has a 30 days wait.

Is Bellingham itself at risk from the Nooksack?

Most of the city isn't in the Nooksack floodplain; the river runs north of town through Ferndale to Bellingham Bay. Bellingham's water damage comes mostly from leaks and frozen pipes. ZIP 98225 has 18 federal flood claims on record.

Keep reading

Serving South Bellingham and Fairhaven, North Bellingham, Lake Whatcom and Sudden Valley, Ferndale, Lynden, Blaine and Birch Bay, Nooksack Valley, Mount Baker Foothills and all of Bellingham.

Sources

  1. USGS: Peak streamflow, Nooksack River at Ferndale, WA (12213100)
  2. USGS Water Data: Nooksack River at Ferndale, WA (12213100), daily values (provisional for water year 2026)
  3. NOAA National Water Prediction Service: Nooksack River at Ferndale (NKSW1) flood categories
  4. OpenFEMA: FIMA NFIP Redacted Claims data set (v3)
  5. OpenFEMA: Disaster Declarations Summaries (v2)
  6. Cascadia Daily News: What we know so far about flooding damage in Whatcom, Skagit (Charlotte Alden, December 16, 2025, updated December 18, 2025)
  7. Washington Office of the Insurance Commissioner: Flood insurance (checked October 29, 2026)