three o'clock before
The wind howled like unloosed demons , and the air grew cold , adding to the sting of the grit , when some sudden eddy hurled it into their hiding place . To endeavor further travel would mean certain death , for no one could have guided a course for a hundred feet through the tempest , which seemed to suck the very breath away . To the fugitives came this comfort -- if they could not advance , then no one else could follow , and the storm was completely blotting out their trail . It was three o'clock before it died sufficiently down for them to venture out . Even then the air remained full of sand , while constantly shifting ridges made travel difficult . Only grim necessity -- the suffering of the ponies for water , and their own need for soon reaching the habitation of man and acquiring food -- drove them to the early venture . They must attain the valley of the Salt Fork that night , or else perish in the desert -- there remained no other choice .