 Idaho, Montana, and Canada. The Walla Walla Fire Department responded to two separate fires Saturday. The first was a shed fire behind a residence on the 600 block of South 12th Avenue at 4 27 a.m. The estimated loss is $2,100. The cause was ruled arson. The second was a residential structure fire just before 4 p.m. on the 1,000 block of Pomona Street. The estimated loss is $248,000.