These sorts of events are predicted historically to happen every 150 to 200 years. But based on the warm temperature in the oceans, we see it's now predicted that these will happen every. Call it 25 to 50 years or much sooner. And these high temperatures are driving a higher increased frequency and severity of these sorts of events.View on YouTube
It is too early to determine whether this prediction about future multi‑decadal frequency of California‑scale ARkStorm‑type mega‑floods has come true.
Friedberg’s claim is about changing recurrence intervals: events that historically occurred roughly every 150–200 years purportedly shifting to every ~25–50 years or sooner, driven by warmer oceans and increased atmospheric river activity. That is, it is a statistical, long‑horizon prediction about the frequency and severity of extreme events over many decades.
As of the current date (November 30, 2025), only about one year and ten months have passed since the prediction (January 26, 2024). That time span is far too short to empirically confirm or refute a change in the recurrence rate of phenomena that are, by definition, multi‑decadal to centennial in their historical frequency. Even if one or more extreme storms occur in this short period, that would not be statistically sufficient to validate a claimed 25–50‑year recurrence pattern, nor would the absence of such events in <2 years disprove it.
Current climate research does support that:
- Atmospheric rivers impacting the U.S. West Coast are expected to increase in intensity and may increase in frequency as the climate warms, due in part to higher sea‑surface temperatures and increased atmospheric moisture.
- Studies and USGS/NOAA summaries of ARkStorm‑type scenarios emphasize that warming is likely to raise the risk of extreme precipitation and flooding events in California over the 21st century.
However, while this research is qualitatively consistent with the direction of Friedberg’s statement (more frequent/severe extreme precipitation events in a warmer world), the specific quantitative claim—that ARkStorm‑scale floods will reliably shift from ~150–200‑year events to ~25–50‑year events or less—cannot be validated or falsified based on observations in the very short period since the prediction was made. That would require multiple decades of data and/or a clear consensus in the literature on that exact new recurrence interval, which we do not yet have.
Because the prediction concerns a long‑term statistical frequency and only a short amount of time has elapsed, the correct classification is: it’s too early to tell whether it has come true.