Home › Homeowner Toolkit › What the Different Alerts Mean

What the Different Alerts Mean

Severe thunderstorm watch, warning, and a SkyVision property alert are three different things. What each one means, and what hail sizes actually do to a home.

Weather alerts fail people in a predictable way: either everything sounds like an emergency, or nothing does. Here is what each alert actually means for your home, in the order you’ll see them.

The three alerts, in order

Severe Thunderstorm Watch (National Weather Service). Conditions are right for severe storms over a broad area in the next several hours. Nothing is happening at your home yet. This is your ten-minute-plan window: park the cars inside, bring in what breaks.
Severe Thunderstorm Warning (National Weather Service). A severe storm is happening now, in a specific area, and may include large hail. If the warning covers you: everyone inside, away from windows and skylights. Do not drive to beat it.
SkyVision property alert. This one is different: it means radar detected hail at your address, with an estimated size. It is not a forecast — it is a record that something reached your home. It usually arrives during or just after the storm.

What hail sizes actually do

Estimated sizes are most useful as a rough damage threshold. Every roof, siding type, and storm is different, but as a rule of thumb:

Under 1" (quarter size): rarely damages roofs in good condition; can bruise soft plants and older, brittle shingles.
1"–1.5" (quarter to ping-pong ball): the damage threshold for many asphalt roofs — worth a careful ground-level look and a check of soft metals.
1.5"–2" (ping-pong to egg size): commonly damages shingles, vents, screens, and cars left outside. Document and consider a professional inspection.
Over 2" (egg size and up): expect damage. Broken windows and skylights, dented siding, roof damage likely. Document everything and inspect carefully.

No alert is not proof of no hail: Radar is excellent but not omniscient, and small pockets of hail can slip between scans. If you saw hail fall at your home, trust your eyes: note the time, photograph stones next to a coin or ruler, and check the After the Storm guides.