Subject
- Freezes (Meteorology) -- Oregon6
- Precipitation (Meteorology) -- Oregon6
- Soil erosion -- Climatic factors -- Oregon6
- Freezes (Meteorology) -- Washington (State)3
- Precipitation (Meteorology) -- Washington (State)3
- Soil erosion -- Climatic factors -- Washington (State)3
- Groundwater -- Pollution -- Measurement1