Walshaw Dean, Sunday - reported owl sighting

Via Hugh Firman at Calderdale Council we have received a report of "....a very large white owl with black broken banded markings" flying out of the ruin on the North West side of Walshaw Dean. The observer flushed the owl, and it was seen at very close range. The lady who reported it to Hugh wondered what the owl could be. I have replied and suggested an escaped snowy owl, or more likely a short-eared owl with light plumage. The person reporting it is very familiar with barn owls and is positive it was not one.
Hugh is going up this afternoon to have a look around.