The storms are sentient. So ... does it communicate? Is it like the tales of dragons, wanting some sort of sacrifice to appease it? Can it be reasoned with? Distracted? Tricked? Are they predictable? If so, that offers a number of world-relevant plot motivators.
- "Find the Storm Whisperer, escort him to the town center or we're doomed!"
- "Go set these scented bonfires. It will pull it to the east side of town, and keep the west-side shelters safe!"
- "This storm is out of season! We don't know which one it is. We need you to go figure it out. Take this bag and go!!"

Also, being a storm, it can drive creatures, refugees, monsters in front of it. For example, instead of starting with a storm, you start with a horde of goblins on the horizon and the townsfolk think it's an attack. Only to realize that goblins aren't running TO the town but AWAY from the oncoming storm.