400 WINTER CLIMATE BETWEEN MISSISSIPPI RIVER AND BASE OF MOUNTAINS. 
in the Bitter Root range of the Rocky mountains during most of December; and, finally, crossed 
the Cascade mountains during January. 
On the divide of the*Rocky mountains at Marias Pass I found no snow when crossing, 
October 20th, (save what little snow of the previous winter remained in the narrow valley at the 
base of the divide,) but the snow commenced falling that night; and much of the time spent in 
the prairies, until I again crossed the mountains by the Little Blackfoot Pass, was cold and snow- 
ing. The snow accumulated but little, and attained a greatest depth of eight inches. The 
thermometer often ranged nearly as low as zero. 
On the final crossing of the Rocky mountain summits, by the Little Blackfoot Pass, an incon- 
siderable depth of snow lay on the ground, perhaps an inch or two; and save occasional snow- 
squalls occurring during the descent of Little Blackfoot and Hell Gate rivers, I encountered 
little until I entered the Bitter Root range of mountains, November 21st. In the St. Mary’s 
valley, at that time, there was no snow, and the weather was mild. 
The passage of the Bitter Root range was made between November 21st and December 18th. 
Excepting occasional small valleys, the whole of this mountain district in the southern Nez Perces 
trail was covered with snow; having, as I judged, a greatest depth of six feet, and an estimated 
average depth of near two feet for the whole breadth of the mountains. 
I reached Wallah-Wallah, on the Columbia, on the 30th day of December. From the Bitter 
Root mountains to this place I found no snow; some on the high plains not far from the mount- 
ains, where, for a short distance, it was eight inches deep. 
In the valley of the Yakima the first snow observed was seen seventy-five miles above the 
mouth of the river, and then, on January 13th, it was two or three inches deep. Crossing the 
Cascade mountains, January 21st, by the Yakima Pass, for a few miles the snow was six feet 
deep, very rapidly decreasing in the western slope; the whole breadth, over twelve inches deep, 
was somewhat less than sixty miles in extent. 
Of this, about forty-five miles were two feet deep and upwards, about twenty miles were four 
feet deep and upwards, and six miles were six feet deep. 
I am, sir, very respectfully, your obedient servant, 
A. W. TINKHAM. 
Governor Isaac I. SrEvENs, 
Chief of North Pacific Railroad Exploration, Washington, D. C. 
88. LETTER OF THE HON. H. M. RICE, AND EXTRACTS FROM LETTERS OF HON. H. H. SIBLEY 
AND A. CULBERTSON, ESQ., AS TO THE WINTER CLIMATE OF THE REGION EXTENDING FROM 
THE MISSISSIPPI RIVER TO THE BASE OF THE MOUNTAINS. (FOR MUCH ADDITIONAL INFORMA- 
TION IN REGARD TO SNOWS, SEE THE SEVERAL REPORTS OF LIEUTENANT MULLAN.) 
[Letter from Hon. H. M. Rice.] 
WasuineTon, June 3, 1854. 
Dear Sir: Your note of yesterday, asking me to make a memorandum in reference to the 
winter climate of Minnesota, has been received. Navigation of the Mississippi river closes from ~ 
the 10th to the 25th of November, and opens from the 1st to the 10th of April. That of the Red 
river of the North closes from 1st to 15th November, and opens from 10th to 25th April. I have 
often travelled in the winter from St. Paul to Crow Wing, a distance of one hundred and fifty 
miles, with a single horse and sled, without a track, and have never found the snow deep enough 
to impede my progress. I have also gone from Crow Wing, beyond the headwaters of the 
Mississippi, to the waters of the Hudson’s bay, on foot and without snow-shoes. I spent one 
entire winter travelling through that region, and never found the snow over eighteen inches deep, 
and seldom over nine inches. 
