TODAY ... CLOUDY BECOMING PARTLY SUNNY IN THE AFTERNOON. HIGHS
AROUND 39. LIGHT WINDS BECOMING NORTHEAST 5 TO 15 MPH IN THE
AFTERNOON.

TONIGHT ... MOSTLY CLEAR. LOWS 17 TO 25. NORTHEAST WIND 5 TO
15 MPH.

THURSDAY ... SUNNY. HIGHS AROUND 38. NORTHEAST WIND 5 TO 15 MPH.

Winds remained light yesterday, under 10kst at the tram, and have minimal potential for snow transport. Temperatures climbed up to 2c at the Tram, and almost 4c above the White Path as the clouds came in last night, but are likely still near freezing in the Behrends start zones.

Expect warmer daytime temps than we have seen a in a while, but still below freezing night time temps. This will add strength to the snowpack, but it will not destroy our buried faceted layer above the old Melt-Freeze Crust.

Fortunately this layer is only about 50cm in most places and not positioned to create large slides without additional snow load.

The hazard is MODERATE today: Natural avalanches unlikely; human-triggered avalanches possible. Use caution in or under steeper terrain and in avalanche zones. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

DIURNAL TEMPERATURE VARIATION

Diurnal temperature variation is a meteorological term that relates to the variation in temperature that occurs from the highs and lows during the day.

TEMPERATURE LAG

Temperature lag is an important factor in diurnal temperature variation. As solar energy strikes the earth?s surface each morning, a shallow 1?3-centimetre (0.39?1.18 in) layer of air directly above the ground is heated by conduction. Heat exchange between this shallow layer of warm air and the cooler air above is very inefficient. On a warm summer?s day, for example, air temperatures may vary by 16.5 ?C (30 ?F) from just above the ground to waist height.

Incoming solar radiation exceeds outgoing heat energy for many hours after noon and equilibrium is usually reached from 3?5 p.m. but this may be affected by a variety of different things such as large bodies of water, soil type and cover, wind, cloud cover/water vapor, and moisture on the ground.

SNOW TEMPERATURE GRADIENTS

The daily cycle of air temperatures produces fluctuations in snow temperatures, the magnitude of which diminishes with increasing depth in the snowpack (McClung and Schaerer, 1993). Snow depths greater than about 30 cm show little to no diurnal snow temperature change, due to the insulating capacity of the overlying snow (Armstrong, 1985).

At less than 30cm the near surface, diurnal temperature fluctuations are capable of producing large or extreme temperature gradients over small distances, driving rapid faceted crystal growth (Birkeland, 1998). These faceted crystals, if buried by subsequent snowfall, can form persistent weak layers leading to increased avalanche hazard (Birkeland et al., 1998).

Warm air temperatures can form melt-freeze layers at or near the surface, affecting crystal growth (Birkeland, 1998) and later influencing meltwater runoff (Marsh and Woo, 1984a; Kattelmann and Dozier, 1999).