,

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valleys the mean temperature of the air near the ground is
8 to 10 degrees Fahrenheit higher in the summer months
than in northeastern British Columbia. . The temperature
of the soil is probably lower by much the same deficit, so
that evaporation-losses may be lower in the north. The
meteorological staff at Fort Nelson grew a small plot of
vegetables but found it advisable to add buckets of water
from the creek frequently during warm, rainless spells.
It seems likely, therefore, that the territory in question will
not be suitable for shallow-rooted crops with high water-
requirement, unless systems of irrigation are installed to
concentrate the run-off upon the most arable lands.

The length of the seasons is difficult to assess because
of the incidence of frost during the summer half-year at
any time that a polar outflow of moderate intensity attacks
the region. If such an outbreak follows upon a period

with water-vapour-content well above normal, there will
_ bean extensive cloud-area and at least scattered precipitation
| that may protect much of the region from frost-damage
| at agricultural levels. Otherwise, the frost may be wide-
spread. If, for the moment, such vagrant frosts are neglected
and it is decided that the growing season is defined by a
mean daily minimum temperature above 32 degrees F. and

a mean daily maximum of 43 degrees F. and over, the
following is found:

Date When Mean Maximum Exceeds and Falls Below 43 Degrees F.

Period
DAWEOnE at teh Sete ANpimenl S81 Septas a nner 162 days
NWiaiy Ol atte emg ees es LN 8, DYNO) ee a 163 days
Swede: Creelg ee men Apr. 28 — Sept. 30......... 155 days
Va Wi hitehorsen lea Apiin 22) Octimiasn sawn a. 164 days
Vi @arcrosstin see an INE PY SOG Goh saa oan. 164 days
PZ Ntlinteere net ey eee Maye = 2 Oct Sipe 154 days
JENERENTS SOs pean eee iNpit PES OSE Deed hoo sh 161 days
For Comparison—

St. Walburg, Sask........ Apr. 12 - Oct. 20......... 191 days
PReikwarmtnunrp etn ele tyes ANG 7 = Owe Dose | 203 days
plicrracerrtre rhe = 1/0 Mar. 20- Nov. 2.........227 days
Wastaniaret atone IMarsyeil-—= @Octn 23 meee 206 days
Barkenvilles 2 asap oe IN ove ANS = Ol NS 185 days
HOK-eNOLMan eas = te Mey Speen V5cescouns - 144 days
Bortisimpsontey. 40 ae oie Maya a s5 fe Oct) are oe 150 days
Bort Goodiliope-«, 9-5... May 10 — Sept. 20......... 133 days
ayeRavercs ase ges May 5- Oct. 5........., 153 days
Horeomithy 8s one PADI 20n =H OCtN a See enn 160 days
Alklavikows wits pee orcs fee IMavae2 a toe pts alone sine 108 days
Fort Resolution...-....... Mena” Ga Saye. W355 enso. 145 days
Fort McPherson........... May 18 —- Septet /eeee 122 days
Average: Mackenzie

less Fort Smith.......... IMbyy Sb aye Oe 136 days

YaWeatsonglake: he eons ose Ep ieelo ie—s OCtaee Deepen 170 days
yFort:Nelsone-. 62... 3. NIG, Chm Ole Gg oe aon a 191 days
Babinetakere stew isk INOS GOGH Os sooo 5s 196 days
Diuarts taken nearer Wns Apr 516 =| O@ct> 045 ae 199 days
Prince(Geordene) so IMibigs Day SUNN Sloe aon o oe. 221 days
Momen@reckew ee eee Marte? 4a ©cta=5 Opel 220 days
IMC Bride tan ier pe sey <n iMate, PB = Ole Wh saan ee 214 days
Great Slave Lake—
ond idwiléach ayers IME cmyh Olgas ooh. Snel ee 147 days
Hort Chipewyanen49--ee Mays . le s@ct, 95) ..5 157 days

Peace-Athabaska— Period
UMeMurrayicc-trvescpninten ADI el Os— i Oct. malSe ec eens 191 days
Fort Vermilion.......... ANDES] OGES a Serene ets 178 days
HighjPratient. 2. fai A pee 65s Octs 24a eae. 202 days
Beaverlodgetes tics arte mA pres] Ol Octaraa acne te 196 days
Hortistagohtu es eee NDE eee Ann OCC Donn arr ee 202 days
Hudson Hope........... DADE lcs OCH DA ty nas 206 days

The region from St. Walburg to Loon Lake in Saskat-
chewan is so close to the northern margin of wheatlands
that successful ripening can not be expected in every year.
Since a temperature of 45 degrees F. appears to be generally
needed for the stimulation of the growth of grasses, the
191 day interval at St. Walburg may be taken as an approxim-
ate indicator. If so, the Yukon falls about one month short,
but from Fort Nelson, B.C., into the region of the north-
flowing Fraser and Stikine Rivers, and Tweedsmuir Park
the period is generally longer than at St. Walburg, provided
the elevation of the places named is not exceeded. At
Barkerville, however, which is 4,180 feet above sea, the
period falls one week behind St. Walburg. Roughly, the
period seems to shrink two days for each 130 feet of ascent.
Other topographical features no doubt play a significant
part, such as snow on the mountains nearby, frozen lakes,
etc. The Mackenzie Valley averages nearly two months
short of St. Walburg, as far south as Fort Smith which is
one month short. The shores of Lake Athabaska, and
Chipewyan and Fond du Lac indicate a deficit of five weeks.

McMurray is identical with St. Walburg, but Fort Ver-

milion is two weeks in deficit. The experience of the Fort
Vermilion experimental station should be correlated with
these figures. In how many seasons in 25 successive years
has the station ripened wheat of various varieties, oats,
barley, or rye? In the Peace River Valley the modal
value appears to be 202 days, or an excess over St. Walburg
of 11 days. It appears from experience at Beaverlodge
farm that this value is true only if the bottom lands are
avoided.

With respect to the question of frost consideration
should be given to the following ‘figures:

Average Date When Mean Daily Minimum Temperature
Crosses 32 Degrees F.

Period

Dawsontelja eee ees Dee ie May 12 - Sept. 16......... 127 days
Stal burger: eee ee May ¥7-— Sept: 20). 9. os 136 days
For Comparison—

Garcrossssne eno May 26 — Sept. 24......... 121 days

Swede Creek............ May 12- Sept. 18......... 129 days

Whitehorse............. May 17 - Se pew) eee ee 127 days

AMetage | YURGn GO: fete a eae cr dee ee 126 days
Wratsontliakenmrsas) sae May 11 = Sept. 257.0 137 days
ort Nelson. ss aiews May 4 - Sept. 30......._ 149 days
Babinesleakce aan sean aneenrS May 17 - Sept. 25......._. 131 days
Stuarta ake ys os een: Mayes —iSepts. jn = une 121 days
INewstaveltone ste ae ANE; 27 = Ose iS = 174 days
pRelkarceat tnt es escent: Mey 13 = Ogi Soo. 145 days
Merracenne ae, Ween pte 6 = Noy, 15.575. 223 days
etince| Georges fe ee Mey 5 Ome 9) 155 days
Wanderhoofin sees. May 13 = Sept. 20......... 130 days
Wiistatiaes oaeyye tee ores May 13)°= Sept, 26... 0.99) 136 days

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