Land of Big Tires

A couple times this year I've ridden in a Delta.
A Delta is a large wheeled vehicle that typically
drives out on the ice shelf. How large are the
wheels? Pretty darn big as you can see in the
picture. I'm approximately 5'4" and these tires
are almost taller than me. Thank goodness I don't
weigh as much as they do however as they tip the
scales at 850 pounds. I've been told that they
cost over $500 per tire to replace. We were riding
in a Delta a couple years ago when one of the tires
went flat. The whole vehicle listed precariously to
one side. I'd like to have one of these on a hill
for sledding. Everybody would definitely have to
get out of the way!