Nepal, Aug. 30 -- The siren started over Belkot at 9:17 in the morning.

For three years it had been a useless object on the roof of the ward office: an iron throat between two bent poles, with crows building their nests underneath it in the winter. The children in the public park would throw stones at it. Their fathers claimed it had warned the town during the war, even though none of them had witnessed a war. Their grandfathers said it had warned about floods, although the river had been calm for so long that calmness had come to be regarded as a form of authority.

When the sound came, thin at first and then insistent, nobody ran. Tara was rinsing the lentils in a brass bowl while her husband Milan, in the yard, turned over an old bicy...