FORT ST. JOHN, B.C. -- There is more information on what caused a Canada Day washout along the Alaska Highway south of Watson Lake, but it could be two months before the highway reopens.

The road was closed entirely until Monday afternoon when a detour opened from the 897 to 900 km markers.

The federal government says heavy rainfall collapsed a beaver dam. A statement from Public Services and Procurement Canada (PSPC) said stones and loose debris built up eventually blocking the highways culvert.

“The runoff then backed up, eventually to the point where it overflowed across the road surface. The flow was so high that it completely washed out a 75m stretch of the highway.”

PSPC says the detour using the former highway alignment is expected to be in place for 6 to 8 weeks while the main highway is repaired.