ATSC 113 SNOW EXAM GUIDE QUESTIONS WITH ANSWERS
2025/2026
gradient - is a change in a property, such as temperature, over a distance
Deposition - occurs when a substance undergoes a phase change directly from the gas
to the solid phase, without the liquid stage in between. For instance, the deposition of
water is when it changes from water vapour (gas) into ice (solid) without passing
through the liquid water phase. It literally deposits itself onto the snow surface.
Dewpoint temperature - is the air temperature at which water vapour starts to condense
into liquid droplets, while being cooled
Frostpoint temperature - is the dewpoint temperature if the air is below 0°C. Instead of
dew, frost forms.
Surface hoar or hoarfrost or just frost - is essentially the frozen version of dew. It is
produced by deposition onto the snow surface when the air temperature falls below the
frostpoint temperature. The outcome is the formation of ice crystals on the top of the
snow surface.
What is needed for surface hoar to form? - clear night skies, calm winds, A strong
temperature inversion,
temperature inversion - temperature generally decreases with height in the troposphere
(Fig. 6c.1). However, occasionally temperature can increase with height for some layer
of air in the troposphere
How do inversions occur? - Subsidence due to high pressure & Radiative cooling of the
ground
On a weather map, what does an isobar represent? - A line connecting locations of the
same pressure
Complete the blanks in following statements, in order.
_____ kPa is at about sea level elevation /
85.0 kPa is at about ______ m elevation /
______ kPa is at about 3000 m elevation. - 100. / 70.0
The 85.0 kPa level is above which mountain peak? - Cypress
What is the approximate pressure level at mid-mountain at Lake Louise? (Mid-mountain
is halfway between the elevation of the lake and the mountain top next to the lake.) -
80.0 kPa
Why is the orientation of the main shaft of a wind barb important? - It indicates the
direction of the wind
, If you see four triangles on a wind barb at the elevation you're planning to ride, what
does this indicate? Assume that the units as are they were presented in the snow
learning goals. - A good day to stay inside and avoid skiing
How might a weak pressure gradient be represented on a pressure map? - The isobars
are far apart
What does a temperature contour on a pressure-level map indicate? - Points that have
the same temperature
What information is necessary in order to interpolate from temperature on a pressure-
level map to a free-air temperature at a different altitude? Select the best answer. - ALL
OF THE BELOW
The forecasted temperature
Dry or wet adiabatic lapse rate
The forecasted relative humidity
You plan to go skiing with friends at Whistler (elevation ~2000 m), and you have access
to an 85.0-kPa (~1500 m) pressure-level map. The forecasted temperature at Whistler
at 85.0 kPa is -2˚C, and the relative humidity is 60%. How should you interpolate the
temperature up to 2000 m? - Subtract 5˚C from -2˚C
Your friend calls and tells you that he has made plans to go to Grouse Mountain!
Grouse has an elevation of ~1000 m. Using 85-kPa pressure-level map: the forecasted
temperature is 1˚C and the relative humidity is 95%. What is your estimate of the free-
air temperature? - 3˚C
What factor(s) do you need to account for when making surface heating or cooling
adjustments to the free-air temperature? Select the best answer. - Cloud cover, sun
angle, and wind speed
It is a spring afternoon with clear skies and light winds. You have already determined
that the free-air temperature is 4˚C. What is your final temperature forecast after
adjusting for surface heating or cooling? - 12˚C
You are forecasting for 8:00 am (just before sunrise) on a winter day with partly cloudy
skies and wind speeds of 50 km/h. The free-air temperature is 0˚C. How should you
adjust your morning temperature forecast for surface heating or cooling? - Subtract 2˚C
Snowpack temperature gradient: - Is the most important factor that influences the
evolution of a snowpack.
Under what conditions are faceted crystals produced? - Large vertical temperature
gradient and fast-moving water vapour
2025/2026
gradient - is a change in a property, such as temperature, over a distance
Deposition - occurs when a substance undergoes a phase change directly from the gas
to the solid phase, without the liquid stage in between. For instance, the deposition of
water is when it changes from water vapour (gas) into ice (solid) without passing
through the liquid water phase. It literally deposits itself onto the snow surface.
Dewpoint temperature - is the air temperature at which water vapour starts to condense
into liquid droplets, while being cooled
Frostpoint temperature - is the dewpoint temperature if the air is below 0°C. Instead of
dew, frost forms.
Surface hoar or hoarfrost or just frost - is essentially the frozen version of dew. It is
produced by deposition onto the snow surface when the air temperature falls below the
frostpoint temperature. The outcome is the formation of ice crystals on the top of the
snow surface.
What is needed for surface hoar to form? - clear night skies, calm winds, A strong
temperature inversion,
temperature inversion - temperature generally decreases with height in the troposphere
(Fig. 6c.1). However, occasionally temperature can increase with height for some layer
of air in the troposphere
How do inversions occur? - Subsidence due to high pressure & Radiative cooling of the
ground
On a weather map, what does an isobar represent? - A line connecting locations of the
same pressure
Complete the blanks in following statements, in order.
_____ kPa is at about sea level elevation /
85.0 kPa is at about ______ m elevation /
______ kPa is at about 3000 m elevation. - 100. / 70.0
The 85.0 kPa level is above which mountain peak? - Cypress
What is the approximate pressure level at mid-mountain at Lake Louise? (Mid-mountain
is halfway between the elevation of the lake and the mountain top next to the lake.) -
80.0 kPa
Why is the orientation of the main shaft of a wind barb important? - It indicates the
direction of the wind
, If you see four triangles on a wind barb at the elevation you're planning to ride, what
does this indicate? Assume that the units as are they were presented in the snow
learning goals. - A good day to stay inside and avoid skiing
How might a weak pressure gradient be represented on a pressure map? - The isobars
are far apart
What does a temperature contour on a pressure-level map indicate? - Points that have
the same temperature
What information is necessary in order to interpolate from temperature on a pressure-
level map to a free-air temperature at a different altitude? Select the best answer. - ALL
OF THE BELOW
The forecasted temperature
Dry or wet adiabatic lapse rate
The forecasted relative humidity
You plan to go skiing with friends at Whistler (elevation ~2000 m), and you have access
to an 85.0-kPa (~1500 m) pressure-level map. The forecasted temperature at Whistler
at 85.0 kPa is -2˚C, and the relative humidity is 60%. How should you interpolate the
temperature up to 2000 m? - Subtract 5˚C from -2˚C
Your friend calls and tells you that he has made plans to go to Grouse Mountain!
Grouse has an elevation of ~1000 m. Using 85-kPa pressure-level map: the forecasted
temperature is 1˚C and the relative humidity is 95%. What is your estimate of the free-
air temperature? - 3˚C
What factor(s) do you need to account for when making surface heating or cooling
adjustments to the free-air temperature? Select the best answer. - Cloud cover, sun
angle, and wind speed
It is a spring afternoon with clear skies and light winds. You have already determined
that the free-air temperature is 4˚C. What is your final temperature forecast after
adjusting for surface heating or cooling? - 12˚C
You are forecasting for 8:00 am (just before sunrise) on a winter day with partly cloudy
skies and wind speeds of 50 km/h. The free-air temperature is 0˚C. How should you
adjust your morning temperature forecast for surface heating or cooling? - Subtract 2˚C
Snowpack temperature gradient: - Is the most important factor that influences the
evolution of a snowpack.
Under what conditions are faceted crystals produced? - Large vertical temperature
gradient and fast-moving water vapour
