The hazard
Storms can build fast, and inclement weather changes every job on site. Lightning can strike before the rain arrives, wind can turn a sheet of plywood into a sail, and rain makes ladders, steel and mud slick. People get hurt when nobody knows who calls the stop or where to go. A plan everyone knows ahead of time takes the guessing out of a bad moment.
The action
When the warning comes, stop work and go straight to the assigned shelter. An emergency action plan must include procedures to account for all employees after an evacuation, so check in with your foreman every time. If someone is missing, tell the person in charge right away instead of going back out to look on your own. (29 CFR 1910.38(c)(4))
ASK THE CREW
Where is our shelter, and how would you get there from where you are working?
From the talk: Severe weather. Read it in full, free, with the questions and the sign-in sheet.