I came across this question on the pinned genocide thread and am really interested and looking forward to any answers. Thank you in advance to anyone commenting!
There is always more to say, but I discussed the problem of how extensive the harrying was in an earlier post, and this touched on the manner in which it was conducted and the Normans' reasons for carrying it out in the first place. You might like to review that thread while you wait for fresh responses to your query:
How bad was William I's "Harrying of the North"?
And u/Steelcan909 answered a very similar question a little earlier, here: