The Nass River
is a river in northern British Columbia
. It flows 380 km (235 miles) from the Coast Mountains
southwest to Nass Bay, a sidewater of Observatory Inlet
, itself an arm of Portland Inlet
, which connects to the North Pacific Ocean
via the Dixon Entrance
Nass is a Tlingit word meaning "food depot". The Nisga'a name for the river is Txaa K'alii Aksim Lisims. The Gitxsan name is Xsitxemsem.
The last 40 km (25 miles) of the river are navigable. The river is a commercially-valuable salmon fishery. The basin of the Nass is the location of the first modern-day treaty settlement in British Columbia, between the government of that province and the Nisga'a Nation. Nisga'a means "people of the Nass".
About 220 years ago according to legend of the Nisga'a people, the Nass River was dammed
by a 22.5 km long lava flow
which came from the Tseax Cone
and destroyed the Nisga'a villages and the death of at least 2000 Nisga'a people by volcanic gas
and poisonous smoke. The volcano was active at least twice (220 and 650 years ago). Because of our knowledge of this previous disaster, modern monitoring
would include studies of the gases emitted by the volcanoes and a warning to people living downslope from the volcanoes
If the Tseax Cone
were to erupt again, there would be a repeat of the poisonous gas disaster (as to what happened to the Nisga'a people) could cause forest fires
and could poentially dam local rivers (as to what happened to the Tseax
and Nass River) if the volume of the lava flows are large enough. If the lava flows were to again reach the Nass River, it could have disastrous short-term consequences for the important salmon fisheries
on the Nass River system. The people who live in the region would have no knowledge of the dangers of the Tseax Cone if they were to erupt again.