What event in 1946 forced the last permanent inhabitants to leave Waimanu Valley?

Answer

A tsunami

Waimanu Valley has a deep history of human occupation, evidenced by ancient remnants and agricultural sites used for cultivating taro. This residential history came to an abrupt end in 1946 when a powerful tsunami struck the coast. The impact of this natural disaster forced the final group of residents to vacate the valley, leaving the area to eventually return to the wilderness state it occupies today.

What event in 1946 forced the last permanent inhabitants to leave Waimanu Valley?
locationWaimanu