Thompson himself with a partner, William Henry, and two Indian hunters had ridden ahead to the gap, scouring the country for game and keeping a sharp watch for possible enemies. The party had killed three red deer, made a scaffold, and placed the meat on it for safety against wild animals. Days passed, and the canoes did not put in an appearance. On the 17th the oldest hunter, rising as usual very early in the morning, looked at the scaffold and remarked, "I have had bad dreams; this meat will never be eaten." So saying, he saddled his horse and rode away.

Thompson could no longer conceal his anxiety. He ordered Henry and the other Indian to proceed down the river in search of the canoes; with positive orders not to fire a shot except in self-defence. At eight in the evening they returned, and he heard their story. Some miles down the river, they had seen a number of Piegans encamped on the bank. A short distance below this camp, they had descended the slope to the river, where they found the marks of canoes and near them in the bottom a rude rampart of stones on which there were traces of blood. Proceeding further down stream, they had fired a shot as a signal to the lost canoemen, but it was not returned.

Thoroughly alarmed by their rashness and folly, Thompson prepared to fly for his life, for he knew that the Piegans would be on them in the morning. At dawn of day, they took horse and made their way east by a wide detour through the forest. Fallen trees and undergrowth interrupted their progress, and their horses' hoofs made their track easy to follow. Fortunately the afternoon brought with it a light fall of snow, giving them some hope of shaking off their pursuers, and late in the evening they ventured to halt and kindle a small fire.

Racked with fear for his own safety and anxiety for the fate of his men, Thompson passed a sleepless night. His first care was to find the brigade. Avoiding Rocky Mountain House, he continued east for sixty miles along the river, and there, on the second afternoon, he came upon his men, safe and sound, encamped in an abandoned trading-post known as Boggy Hall.

All hope was now abandoned of passing in safety by the defiles of the Saskatchewan, and Thompson determined to blaze a new trail across the Rockies by way of the Athabaska river. The route projected lay over an old path of the Assiniboine Indians to a point on the Athabaska not far from the present line of the Canadian National Railways; and from thence along the valley of the river past the mouth of Yellowhead Pass to its headwaters some miles further south. From this point a pass led across the height of land to the Wood river, a small tributary of the Columbia. In later years this pass (known as the Athabaska Pass) was the regular route for traders of the Hudson's Bay Company on their journeys to British Columbia.

Horses and dogs were rapidly collected for the trip over land. The men were detailed to their several duties, four to hunt, two to clear a path through the woods, and the remainder to look after the animals and perform the labour of the camp. By the 28th of October all was in readiness; and the little party set off with Thomas, an Iroquois Indian, to act as guide.

It was a full month before they had crossed the belt that lay between them and the Athabaska. The road ran through a wretched country, over mountains and across muskegs. Here and there the fires of the forest had cut wide swathes through the woods, leaving in their wake a tangled mass of fallen timber, through which they had to hack their way. In the bogs the horses lost their footing, shifting their packs and bruising their knees, until in a short while they were almost useless. To complete the misery of the travellers, there was the difficulty of securing food. Their dried provisions were soon exhausted. Game was scarce; and the hunters often returned empty-handed after a long day's chase.

By the first of December they had reached the Athabaska. Four days later they had come to a point on the river a little above Brulé lake, where the guide informed Thompson that owing to the lateness of the season, all thought of crossing the mountains with horses had to be given up. The greater number of the beasts were therefore sent back to Rocky Mountain House; four only were retained to ease the burden of the dogs.

The thermometer now registered 32° below zero; and the party threw themselves into the work of building a rough shelter of logs to serve while they prepared sleds and snow shoes with which to complete their journey. At the end of the month they made a fresh start. Urged by the shouts and lashings of the voyageurs, the dogs with their burdens scurried along the ice of the river. In five days they came to the grassy ponds that marked its headwaters—the last possible pasturage for horses. Here, therefore, the poor animals were turned loose to survive the winter as best they could.

Four days more brought the party to the height of land. The landscape, as far as the eye could reach, was clothed with a heavy mantle of gleaming snow. Round about towered the lofty peaks, their sides scarred by avalanches which had swept the slopes bare of trees and rocks in their descent. To the right lay an enormous glacier, a mass of blue-green ice, the eastern face of which was not less than two thousand feet in height. The night was fine, and the stars shone with such brilliance that one of the men told Thompson that he felt he could almost touch them with his hands.