An emergency alert for a thunderstorm?

My brother said it was hail the size of golf balls falling in his neighbourhood, all the car windows are smashed. They should have made it more clear in the warning but I think it was a valid reason

I've seen them for tornado warnings, but not thunderstorms. Although the Environment Canada alert does warn that severe thunderstorms can spawn tornadoes.

If you abuse the alert system, people will just ignore it or turn it off.