The White River Ash is a 1,500-year-old
tephra deposit found in the southern part of the Yukon Territory, Canada and eastern Alaska.[1] The deposit is bilobate,[2] formed by two large (
VEI 6)
explosive eruptions from the
stratovolcano of
Mount Churchill that occurred around 850 AD and blanketed 340,000 km2 (130,000 sq mi).[3] While originally believed to only exist within North America, recent observations (2014) have found crypto-tephra from the eruption across northern Europe.