: 44.

Extreme Minimum

Peace Fond | ak :
Month A thabaska River du Resolution |} Simpson | Good Hope
Crossing Lac
Jantary.c. 6. os —47 —53 rT’ SS te ere SS —51-0 — 62
REDTUBE 2.250. 3006: —34 —33 nk” shan Ape eee —50°5 —46
OECD. See ce —28 —30 SS V biscad [ee as Bate ns —50-0 —47
Aprilct ey ee 21 17 —13 —13-0 5-0 —20 ;
May Screg 22 26 18 12-0 27-0 14
JUNGE eee 25 , , 29 31 34-0 27-0 29
July. Ses ee 30 34 37 32-5 31-5 39
ANPUSE Se es ee 29 Laie gee eRe I te 35-0 27-0 23
September.......... : 18 if Seereipes Boia Saeae GaklN 25-0 23-0 12
October 33... 8 8 15 13-0 3-0 —22
November........:. —\g 3! — 6 —11 — 8-0 —29-0 —47
December........... —30 —37 —20 —32-0 —48-0 —50
WiGSRt do ee —47 —53 ei Sieg Oy RUE perpin ae —51-0 —62
Monthly Mean
Peace Fond
Month Athabaska| River du Resolution | Simpson | Good Hope
Crossing Lac
JANUATY... 022. 25 SS — 0:5 — 7-7 Se Sat OE EU ae ra eo —24-8 —35-7
Kebruary.<.). 5.62%! 16-0 11-1 = be ee) eee —21-4 —26-1
Marah eso ss 15-8 15-5 — 5:3 pete ieee ei — 2-3 — 7-6
ADEs oe. is nee 39-7 39-8 22-0 21-0 29-5 19-5
Mayer ee Bae et 49-8 52-9 ~ 40-0 41-9 43-9 37-2
dane Se. bo es 59-8 59-7 56-7 56-7 57-3 56-6
DOL aan 55-8 | 58-1 57-0 54-7 57-6 59-6
AUPUBE gee §8-25. 3 HOES ave ek ee 58-0 54-5 49-2
September.......... 46-9. AS eB ie Ee BR te 48-6 45-7 387-9
October. 5625.22: 38-8 37-6 33-9 34-4 24-1 12-3
November.......... 203° 23-1 19-1 16-9 — 1-7 —15-9
December........... 17-0 9-1 1-4 — 7-4 —13-7 — 24-3
WiGAP oa). cosas 35°3 oe eee fee a eA Re Ee ee 20-7 13-6
Th ee ee

The freezing and breaking up of the rivers and lakes are events intimately
connected with the climate and therefore of interest in that connexion. In all
the rivers of the Mackenzie basin navigation is interrupted by drift ice in the
autumn some time before the actual closing of the streams; and in the spring
ice-cakes continue to run for several days after the breaking up of the rivers.

'  Athabaska and Peace rivers break up between the middle and the end of
April, and ice may be expected to run in these streams any time after the middle
of October, though it may be as late as the middle of November.

Liard river is a week or ten days later in breaking up in the spring and a
few days earlier when ice begins to drift in the autumn. The ice from the
Mackenzie below the mouth of the Liard is disrupted in spring through the
influence of the Liard river, but it is usually from two to three weeks before the
break reaches the head of the delta of the Mackenzie. The Mackenzie above the
mouth of the Liard generally remains solid for a week or ten days after the ice
breaks up below that point. .