TWIN FALLS, Idaho (KLIX)- As firefighting resources are stretched thin across the Western United States, the Canadians have arrived to help. Two heavy and a medium duty Canadian airtankers are currently based at the Twin Falls Air Base. Mark Michelsen is the Assistant Aviation Manager for the Twin Falls District Fire and Aviation management says the Canadians are working under a cross boarder agreement from the Province of Saskatchewan. Michelsen says Canadian airtankers have been helping the US more frequently in the past 6 years. The US fleet of heavy airtankers has been shrinking since 2002 says Michelsen, when there were more than 40 aircraft. Now there are only 9 heavy airtankers. That number does not include lighter duty firefighting aircraft. The two Convair 580-A will stay at the Twin Falls Air Base until called elsewhere.