Boats had to be prepared before weather closed the safest routes.

In such a place, a society could appear prosperous during one month and vulnerable a few months later.

There is another reason the first settlement was possible: the Norse were experienced at turning marginal land into productive land.

Across Iceland and the North Atlantic, farmers had learned to combine livestock, seasonal hunting, fishing, and trade.

Greenland required that flexibility at a higher level.

The settlers did not simply reproduce a Norwegian farm in miniature.