 Governor Walz says the total impact of flooding in Minnesota may not be known for several weeks. Walz and other state leaders toured areas of central and southern Minnesota by helicopter yesterday. The governor said the scope of the damage was much more visible from the air and could get worse since some rivers and streams have yet to crest. Walz also said he could call a special session of the legislature if damage totals exceed the amount of disaster relief currently available in state. Senator Amy Klobuchar said the state may be close to qualifying for federal help.