Winter Woman by F.M. Parker

Raised on Mississippi riverboat, Jacob Morgan came west to make his fortune as a fur trapper. But there, on the violent, bloodstained prairie, he is the survivor of a savage confrontation that will change the course of his life.

Driven from his lands by the white invaders, Wolf Voice has been forced to steal and kill in order to survive. With most of his tribe brutally massacred, he will have his vengeance - or die.

Cora Dubois, driven by dreams of a new life, begins a journey with her homely sister Maude from New Orleans toward the golden mountains of California. They join with a caravan of Mormon men and women to make the journey as far as Salt Lake City.
The Mormon leader falls in love with Cora and ask to marry her. Cora refuses. Maude tries to force Cora to agree to the marriage. Wolf Voice tries to kidnap Cora but Jacob prevents it.

The Mormon journey goes terribly wrong when a winter blizzard traps the people In the mountain wilderness. To escape Wolf Voice and Shattuck the renegade, Jacob and Cora must join together and they strike off into the mountains to a place known to Jacob. In the stark fierce winter, Cora's sister goes insane and believing Jacob is the cause of Cora not marrying the Mormon man, tries to kill Jacob. Wolf Voice and Shattuck find Jacob and Cora and a battle to the death begins.
FROM WINTER WOMAN

Jacob and Glen and Moon Mist rode downward through the winter day with the flanks of the mountain pulling back and the valley widening. When the prairie lay ahead, the trappers halted their horses. Moon Mist stopped her mount behind for she knew what was about to happen.
Both men twisted in their saddles and looked at Moon Mist. Her eyes locked on Jacob's, holding his with a pleading expression.
"Get on your way, girl," Glen said and pointed to the south. "Your people are in that direction about five suns riding."
Moon Mist stared at Jacob and did not move.
"Did you hear me, girl? Stop watching Jacob and answer me."
Jacob spoke to the girl. "Can you find your way home, Moon Mist?" He saw the sorrow at her leaving in her face. He felt a tinge of regret himself. Her presence, her girl's voice and laughter had made the long, snowy winter damn pleasant.
In the fall of the year just past, Glen and he had journeyed to the Bighorn Mountains along a route through Cheyenne country. At a Cheyenne village on the Sweetwater River, they had traded a pistol for Moon Mist, a girl the Cheyenne had taken captive from the Arapaho. She had gone with the trappers to escape the cruel slavery from the Cheyenne. The three had continued on into the land of the fierce Crow Indians, built a cabin in a hidden valley in the Bighorns, and trapped furs all winter.
Moon Mist kicked her mustang forward and reached out and caressed Jacob’s bearded cheeks. "Take me with you, please. I will do what ever you want."
"Don't listen to her," Glen said. "You don't need an Indian squaw."
Jacob caught Moon Mist's hand and removed it from his face. "Go home. We will give you a rifle with plenty of shot. You are pretty and with a valuable rifle to give, you can find a husband."
Moon Mist jerked her hand free. Her eyes narrowed and took on a hard sheen. "Give me the rifle," she said sharply.
"Can you find your way back?"
"What do you care?"
"I do care." He understood her feelings. She had come willingly with the trappers. Now they were forcing her away and she did not want to leave him. Maybe he shouldn't have been so kind to her. "I want you to make your way safely back to your people."
"Give me the rifle," Moon Mist said sharply.
"All right.