A common problem in cold-weather areas is your dryer vent flapper freezing shut. The flapper may freeze shut if it rains and there’s a sudden cold snap. Also, if it snows and you run the dryer, the warm air may melt some of the snow, which could refreeze after the dryer shuts off. When the vent flapper is frozen shut, the dryer cannot properly vent its exhaust and will become damaged. However, you can easily clear frozen dryer vents by using a hair dryer.
Make sure your dryer vent is frozen shut, rather than blocked for another reason. Inspect the area around the dryer vent hood and look for any objects that might prevent the dryer vent flapper from opening.
Clear away snow and ice from the dryer vent. If snow and ice are left around the dryer vent, they can melt and refreeze, causing the flapper to become frozen shut again.
Melt the ice on the vent flapper by blowing hot air on it with a hair dryer. Once the ice is melted, keep blowing hot air on the vent until the water on it evaporates. If you don't remove all the water, the vent may refreeze.