California has a storm of "biblical proportions" every 200 years

[gellfex]

@anon61221983

I think it’s only been in the past 2 centuries that we’ve kept weather records to be able to compare… but there are other ways of knowing what happened with weather patterns from the period between 1650-1700 - historical documents of travelers in that area, Native American history/lore, and also climate science that looks at the land itself as a historical document for understanding long term weather patterns in particular areas.

Tree rings are an important tool. Wide in wet years, narrow in dry. They’ve gotten overlapping years samples for thousands of years of rainfall patterns. It doesn’t show 100 year storms, just yearly patterns.