Crossing them in winter, without a trail, without a map, without adequate supplies, in the company of two small children, is something different.

The sources provide relatively few specific details about the mechanics of the Blue Mountain crossing.

The National Park Service account says the journey covered approximately 250 miles and lasted about three months.

Other sources refer to nine days of struggling through snow drifts before she stopped to build a shelter.

The details that survive point to specific challenges: running out of conventional food supplies, using the horse as both transportation and eventual food source, building improvisational shelter from available materials.

The horse was essential and then was killed.