What accident does Tom have? Why does this put him in danger?

He spat upon the snow, a favorite northland trick,

and the sharp crackle of the instantly congealed

spittle startled him. The spirit thermometer at

Calumet had registered sixty below when he left,

but he was certain it had grown much colder, how

much colder he could not imagine . . .

After an hour he rounded a bend, where the

creek ran close to the mountainside, and came upon

one of the most insignificant-appearing but most

formidable dangers in northern travel.

The creek itself was frozen solid to its rocky

bottom, but from the mountain came the outflow

of several springs. These springs never froze, and

the only effect of the severest cold snaps was to

lessen their discharge. Protected from the frost

by the blanket of snow, the water of these springs

seeped down into the creek and, on top of the creek

ice, formed shallow pools.

The surface of these pools, in turn, took on a skin

of ice which grew thicker and thicker, until the water overran, and so formed a second ice-skinned

pool above the first.

Thus at the bottom was the solid creek ice, then

probably six to eight inches of water, then the thin

ice-skin, then another six inches of water and another

ice-skin. And on top of this last skin was about an

inch of recent snow to make the trap complete.

To Tom Vincent’s eye the unbroken snow surface

gave no warning of the lurking danger. As the crust

was thicker at the edge, he was well toward the

middle before he broke through

In itself it was a very insignificant mishap—a

man does not drown in twelve inches of water—but

in its consequences as serious an accident as could

possibly befall him.

At the instant he broke through he felt the cold

water strike his feet and ankles, and with half a

dozen lunges he made the bank. He was quite cool

and collected. The thing to do, and the only thing

to do, was to build a fire. For another precept of

the north runs: Travel with wet socks down to twenty

below zero; after that build a fire. And it was three

times twenty below and colder, and he knew it.