BUMPED due to the damage survey links added.
UPDATE: Tuesday afternoon: First-hand account of chasing the storm is here. Gripping reading.
My friend, Robin Lorenson, sent me this video of the tornado.
For more video and photos of yesterday’s Iowa storms, click here.
UPDATE SUNDAY AFTERNOON: The NWS has rated this tornado EF-3 intensity.
UPDATE MONDAY EVENING: The National Weather Service damage surveys are here for the Mapleton tornado and here for northern Iowa as a whole.