MERWIN
OperatingHydro power plant
- Capacity
- 136 MW
- Primary fuel
- Hydro
- County
- Cowlitz County
- Operator
- PACIFICORP
- Status
- Operating
- Commissioned
- 1931
- EIA plant ID
- 3847
- Coordinates
- 45.9567, -122.5557
MERWIN, a 136 MW Hydro power plant in Cowlitz County, Washington. Operated by PACIFICORP, commissioned 1931.
Weather peril exposure
MERWIN is a 136 MW hydro power plant in Cowlitz County, WA, operated by PACIFICORP, commissioned in 1931. Cowlitz County carries elevated modeled catastrophe exposure in the FEMA National Risk Index, scoring 2.6 of 5 at the 40th national percentile. Coastal flooding is the leading peril, rated Relatively Low by FEMA at the 98th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a hydro plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
Cowlitz County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Coastal flooding | Relatively Low | 98th | 4.9 of 5 | 1.6 |
| Earthquake | Relatively Moderate | 97th | 4.9 of 5 | 0.02 |
| Riverine flooding | Relatively Moderate | 87th | 4.5 of 5 | 0.75 |
| Heat wave | Relatively Moderate | 66th | 3.6 of 5 | 5.0 |
| Strong wind | Relatively Low | 39th | 2.5 of 5 | 0.04 |
| Wildfire | Very Low | 35th | 2.4 of 5 | <0.01 |
| Winter weather | Relatively Low | 19th | 1.8 of 5 | 21.1 |
| Ice storm | Relatively Low | 15th | 1.6 of 5 | 0.33 |
| Hail | Very Low | 11th | 1.4 of 5 | 0.05 |
| Tornado | Very Low | 10th | 1.4 of 5 | 0.09 |
| Lightning | Very Low | 3rd | 1.1 of 5 | 6.1 |
Perils not assessed in Cowlitz County
These perils carry no usable National Risk Index figure for this county, so they are excluded from the scoring rather than scored zero. A zero would claim the peril was assessed and found benign.
| Peril | Why it is not scored |
|---|---|
| Hurricane | FEMA rating is "Not Applicable" for this county |
Model hail, wind and flood exposure for Cowlitz County in the weather risk calculator
Ratings are the FEMA National Risk Index county hazard ratings; the peril score is a Bywatts transform of the FEMA national percentile. Full data sources and the solar vulnerability methodology are in the weather risk calculator.
Modeled estimate for screening and negotiation. Built from FEMA National Risk Index county hazard data and a solar vulnerability layer documented above. Not a quote, a binder, or actuarial advice, and not a substitute for a carrier's own model. Hazard data: FEMA National Risk Index December 2025, synced 2026-07-24. Resolution is county level, not site level.