12-08-2025 11:03am

Big Dan's Rainageddon Forecast

Chris Clasen Editor

I'm not sure when heavy rain typical of the Northwest started being called an "atmospheric river," but "Big Dan" grew up here and had this to say. "Rainageddon headlines grab attention, but here in the LFP, it's just another December day". He went on to explain:

All the mumbo jumbo, alarming weather headlines can be summed up as follows. Pay attention to how much rain is being predicted:

0.25 inch (a quarter-inch)
→ Light rain. Enough to barely dampen soil, wet roads, and create light runoff in gutters.
→ Often the amount from a short rain shower.
0.5 inch (a half-inch)
→ Moderate rain. Streets will show steady runoff, storm drains start flowing noticeably.
→ Can slightly overwhelm drains if it falls quickly. Enough to water a garden.
1 inch
→ Heavy rain. Produces four times as much water as 0.25" and twice as much as 0.5".
→ Can cause ponding, minor flooding in low spots, and full storm-drain flow. Flooding is affected by how intensely the rain falls

So whatever your weather app of choice is, find one that predicts rainfall in inches, like this one. Weather Underground taps into home weather stations of which there are five or so just in LFP alone. This map is set to show current temperature:

The Rainageddon event being talked about so much in the media doesn't appear to be affecting our fair city any more than typical weather for this time of year. Note the highlighted "rain in inches" part of the graph: