This article is from the Lure Coursing FAQ, by Bonnie Dalzell with numerous contributions by others.
All sorts. Since trials are scheduled events they are canceled only in
the case of extreme weather conditions - tornados, hurricanes,
blizzards. I'm not kidding! Last winter I was scheduled to judge at a
trial in New Jersey in early March. A blizzard came up the day before.
It was not until 7 PM the night before the trial that it was decided
to cancel the trial. Not because all the roads were closed (they were)
but because with 24 inches of ice and snow on the coursing field it
seemed that it would be difficult to set up a safe course.