Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >
Biggest takeaway:
Whatever plan you base off a tornado warning, that NWS tornado warning needs to be received instantly, & your plan triggered and accomplished rapidly (within a few minutes) to be of value.
Warning/Trigger for Plan:
NWS Tornado Warning
Advance Notice/Time to Activate & Accomplish Your Planned Response:
Plan on 5-10 minutes of advance warning.
Allow options that there may be little/no advance warning, and it may be as much as 30 mins.
Frequency:
Average is 0-2/year for any one location in this region.
How Accurate Warnings?
If a tornado occurs, it is highly likely that it was preceded by at least a few minutes by a NWS Tornado Warning. That said, with the current state of the science, more than half of NWS Tornado Warnings are false alarms. Furthermore, even when a tornado does occur within a warning area, it is less likely to hit your specific location.