Lookups spiked on October 29, 2012.
The word saw frequent use as Hurricane Sandy approached the east coast.
For example, according to a CNN.com headline, "From Maine to South Carolina, states hunker down for storm."
Hunker originally meant "to crouch" or "to squat." The extended meaning, "to settle in or dig in for a sustained period" usually refers to taking shelter or waiting through something unpleasant or difficult.
(For those of our readers who were affected by Sandy, we hope you managed to hunker down and are now recovering well.)