From: on behalf of Panel Registry Subject: FW: TNG registration of ...

station closest to the Study Area with longer‐term historical climate data. While this station
alone cannot adequately represent the diversity of the varied climate conditions found
within the Study Area, it does provide a reference point to examine the mean and variability
of
seasonal climate during the baseline period. This is important as both the mean and
variability of seasonal temperatures affect many ecological and hydrological processes.
Table 2 shows that the mean annual and maximum winter temperatures are less than 0°C
for Tatlayoko Lake. The figures also reveal that the variability (standard deviation) of
minimum, maximum and mean temperatures is much higher in winter than in summer.
Finally,
the table highlights that minimum temperatures in winter are more variable than
maximum
temperatures while the opposite is true in summer.
Table 2: 1961­1990 Baseline temperature data for Tatlayoko Lake Weather Station
Tatlayoko
Lake
1088010
Min
Temp
( o C)
Annual Winter Summ er
Mean
Temp
( o C)
Max
Temp
( o C)
Min
Temp
( o C)
Mean
Temp
( o C)
Max
Temp
( o C)
Min
Temp
( o C)
Mean
Temp
( o C)
Max
Temp
Mean ‐3.0 3.9 10.8 ‐11.1 ‐5.8 ‐0.4 0.6 0.8 1.4
St
dev
Source: PCIC 2008
Note – The station elevation is 870m
( o C)
0.7 0.6 0.7 1.9 1.7 1.5 7.9 14.6 21.2
While temperature is a vital climate determinant, so is precipitation. In addition to the total
precipitation, the proportion that falls as snow, the timing of snow melt and the variation in
snow depth between years all have important ecological and hydrological implications and
are likely to be affected by climate change. During the 1961‐1990 baseline period, the
proportion of total precipitation from snowfall was 27% at Tatlayoko Lake. As indicated by
the coefficients of variation (Cf var), snowfall varies more from year to year relative to the
mean than annual precipitation. Overall, precipitation is relatively low compared to other
areas in BC.
Table 3: 1961­1990 baseline precipitation and snow depth for Tatlayoko Lake
Weather Station
Tatlayoko
Lake
Precipitation
(mm)
Annual
Rainfall (mm) Snowfall (mm)
Mean 438.9 317.0 121.9
St Dev 97.6 99.3 49.1
Cf var 0.2 0.3 0.4
Source: PCIC 2008
Note: St. Dev = standard deviation; Cf Var = coefficient of variation
16