01/14/2026
It's been a good while since a Plumas Corp post. Our apologies and we'll try to be more "social". The Holiday period had lots of fun weather to parse out. By going on vacation, I was only able to experience it vicariously through data. The first storm series met optimistic expectations (12- 20 inches of water in 6 days) in central Plumas County for the Christmas week. Similar to what was received in 1997. Why not the same major flood? Multiple factors feed into the streamflow (hydrologic) response to large storms. In 1997, watershed soils were fully saturated, with substantial wet snow on the ground at all elevations and streamflows already elevated when the storm began. This resulted in virtually all rainfall, plus melting snow, being available for immediate runoff at all elevations. Conversely, the recent Christmas week storm started with drier soil conditions (good initial infiltration) and no appreciable snow at any elevation. Additionally, the highest rain intensity and volume occurred early in the period, allowing the dry soils to buffer runoff, while snow levels gradually drop toward the end. The contrast; a 100-year flood (1997) vs. a 5-yr flood (2025) in what were essentially 10-year storms. Yes, storm magnitude and flood magnitude are not the same for all of the above and still other factors. The Indian Creek and Spanish Creek stream gage hydrographs for that period illustrate much, being just over and just under 5,000 cubic feet per second, respectively. In 1997, the same two stations were 40,000 and 22,100 cfs, respectively. One last factoid: the flow amount at 1 cubic foot per second is equivalent to 449 gallons per minute.
