A Pacific storm and atmospheric river will impact the Pacific Northwest states and northern Rockies this weekend, bringing locally heavy low elevations rain and heavy high elevation snow in the mountains. By Sunday over the Interior Northwest, rain combined with snowmelt will increase the risk of flood hazards. Flood Watches are in effect. 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.