Gosh! 20000 30000 acres is a real lot.
they happen because of negligence or there are also arsons?
I just got back from a 3,000 acre fire yesterday.
This morning on the sit-report I saw one burning in Southern Idaho that's supposed to be 200,000 acres ...
Now that's a big a$$ fire !!!

@ Gulf:
You're right, 6,000 acres in Nevada isn't usually much to write home about for us.
Does seem pretty big for MN though....
Last week we sized up a complex of two fires where "the smaller one" was 15,000 acres. That was a pretty big TFR, let me tell you.....
The big one ended up being 30,000 in the end and when it blew up it created it's own cumulus build-up which then caused more lightning which then started 3 more fires in front of the fire created cell. It was pretty impressive.
Of course we don't try to fight these, we just watch in that case and see what we can do in the morning.
Good times, good times, ...