arkstorm

Etymology
From, from +  1-in-1000 years +. From staring as a disaster planning scenario for a once in a thousand year storm event rainstorm fed by a atmospheric river hitting  and deluging the state, resulting in a seemingly Biblical, needing an , as the  turns into an inland sea.

Noun

 * 1)  A very severe  lasting for many days, fed by an, causing massive.