ATSC SNOW Essential Test Toolkit Exam Questions and
solutions approved for credibility; Latest 2025/2026
Temperature inversion - correct answer when temperature increases with
height
Statically stable air - correct answer when a cool layer of air is beneath a
warm layer of air (cool air is more dense) and there is no vertical motion
Temperature inversions are statically ___ - correct answer stable;
because the temperature increases with height and so the cold air is under
the warm air
Adiabatic lapse rate - correct answer rate in which the temperature
changes in the atmosphere (?)
What can you expect when there is an inversion on a mountain - correct
answer - warmer temps at the middle/top and colder in the valley
- surface hoar formation in the valleys due to cold processes
- warmer temps at upper elevations can cause melting and wet-type
avalanches
- valley cloud and fog
Valley cloud and fog - correct answer - when in mountain valleys, during
an inversion, moisture gets trapped within the valley; sometimes pollution
also gets trapped (inversion is stable since cold air is below warm air, which
can create fog/cloud that lasts for days)
,Capping inversion - correct answer when an inversion occurs anywhere
else within the troposphere and it behaves like a lid or a cap, trapping the
air below; the air below does not travel any higher than the inversion layer
of cold air below warm air
How do inversions occur - correct answer 1. Subsidence due to high
pressure
2. Radiative cooling of the ground
Subsidence - correct answer - subsidence is sinking motion that is
associated with high pressure systems
- when air descends, it warms and becomes drier because of the dry
adiabatic lapse rate
- when the high pressure system is strong and sustained over time, the
descending layer may become warmer than the layers below it (like those
in a mountain valley) which may cause a warm layer over a cold layer, or
an inversion
- one of the ways inversion happens
Radiative cooling of the ground - correct answer - second way inversions
occur
- when on clear calm nights, the ground cools
- in the winter, when there is snow on the ground, an inversion is
strengthened
- also in the winter, the incoming solar energy comes at an angle so the
ground heating is reduced; ground does not get very warm
- in winter, inversions in mountain valleys can persist for weeks under high
pressure
,In winter, inversions can persist for weeks because - correct answer - if
there is high pressure
- if there is snow on the ground, which causes the air to cool more
- if there is clear and calm skies
- if the incoming solar radiation comes at an angle, causing the warming to
be reduced
* most of these do happen
Oreographic uplift and adiabatic cooling - correct answer - when air lifts up
and over mountains; as it ascends it cools adiabatically meaning for each
km it rises, it cools by 10 degrees
If an oreographic uplift occurs with humid air, then... - correct answer as
the air cools, it reaches its dew point and condenses to form clouds and
often precipitation too
Wet adiabatic lapse rate - correct answer once the air is saturated
(humid), the air cools at a slower rate (this is about mountains and
oreographic uplift)
Lee shadowing - correct answer - when air descends on the other side of
the mountain after oreographic uplift, it is drier since the moisture was
removed in the form of precipitation, and as it moves down, it warms
adiabatically by 10 degrees per km (warms faster than it had cooled on the
windward side)
- final result is warmer and direr air after crosses the mountain
Airmass transformation - correct answer - when air, because of lee
shadowing, is warmer and drier
, - air cools adiabatically during oreographic lift and loses its moisture as
precipitation, as the air descends, it warms adiabatically as it descends on
the leeward side
Will there always be precipitation or clouds during oreographic lift - correct
answer no, if the air approaching the mountain is dry it won't. This happens
at inland locations away from the coast
Oreographic lift results in more precipitation at - correct answer higher
elevations, because there are colder temps
Oreographic lift is strongest when - correct answer winds are
perpendicular to mountains
Wind exposed location - correct answer - mountain peaks and ridgetops
where there is less landmass or ground to slow down wind by friction
- wind is worse higher up in the troposphere on mountains and ridges than
on the ground because of friction
What is the exception to a ridge being a windexposed area - correct
answer if you are on a ridge surrounded by other ridges, the friction and
turbulence might slow down the winds somewhat but still, it will be stronger
than winds below
What is the most extreme example of a wind exposed location - correct
answer volcanic peaks because they rise so far above surrounding terrain
What is the venturi/bernoulli effect - correct answer - when air/wind flow
over a mountain goes through convergence and accelerates/speeds up
solutions approved for credibility; Latest 2025/2026
Temperature inversion - correct answer when temperature increases with
height
Statically stable air - correct answer when a cool layer of air is beneath a
warm layer of air (cool air is more dense) and there is no vertical motion
Temperature inversions are statically ___ - correct answer stable;
because the temperature increases with height and so the cold air is under
the warm air
Adiabatic lapse rate - correct answer rate in which the temperature
changes in the atmosphere (?)
What can you expect when there is an inversion on a mountain - correct
answer - warmer temps at the middle/top and colder in the valley
- surface hoar formation in the valleys due to cold processes
- warmer temps at upper elevations can cause melting and wet-type
avalanches
- valley cloud and fog
Valley cloud and fog - correct answer - when in mountain valleys, during
an inversion, moisture gets trapped within the valley; sometimes pollution
also gets trapped (inversion is stable since cold air is below warm air, which
can create fog/cloud that lasts for days)
,Capping inversion - correct answer when an inversion occurs anywhere
else within the troposphere and it behaves like a lid or a cap, trapping the
air below; the air below does not travel any higher than the inversion layer
of cold air below warm air
How do inversions occur - correct answer 1. Subsidence due to high
pressure
2. Radiative cooling of the ground
Subsidence - correct answer - subsidence is sinking motion that is
associated with high pressure systems
- when air descends, it warms and becomes drier because of the dry
adiabatic lapse rate
- when the high pressure system is strong and sustained over time, the
descending layer may become warmer than the layers below it (like those
in a mountain valley) which may cause a warm layer over a cold layer, or
an inversion
- one of the ways inversion happens
Radiative cooling of the ground - correct answer - second way inversions
occur
- when on clear calm nights, the ground cools
- in the winter, when there is snow on the ground, an inversion is
strengthened
- also in the winter, the incoming solar energy comes at an angle so the
ground heating is reduced; ground does not get very warm
- in winter, inversions in mountain valleys can persist for weeks under high
pressure
,In winter, inversions can persist for weeks because - correct answer - if
there is high pressure
- if there is snow on the ground, which causes the air to cool more
- if there is clear and calm skies
- if the incoming solar radiation comes at an angle, causing the warming to
be reduced
* most of these do happen
Oreographic uplift and adiabatic cooling - correct answer - when air lifts up
and over mountains; as it ascends it cools adiabatically meaning for each
km it rises, it cools by 10 degrees
If an oreographic uplift occurs with humid air, then... - correct answer as
the air cools, it reaches its dew point and condenses to form clouds and
often precipitation too
Wet adiabatic lapse rate - correct answer once the air is saturated
(humid), the air cools at a slower rate (this is about mountains and
oreographic uplift)
Lee shadowing - correct answer - when air descends on the other side of
the mountain after oreographic uplift, it is drier since the moisture was
removed in the form of precipitation, and as it moves down, it warms
adiabatically by 10 degrees per km (warms faster than it had cooled on the
windward side)
- final result is warmer and direr air after crosses the mountain
Airmass transformation - correct answer - when air, because of lee
shadowing, is warmer and drier
, - air cools adiabatically during oreographic lift and loses its moisture as
precipitation, as the air descends, it warms adiabatically as it descends on
the leeward side
Will there always be precipitation or clouds during oreographic lift - correct
answer no, if the air approaching the mountain is dry it won't. This happens
at inland locations away from the coast
Oreographic lift results in more precipitation at - correct answer higher
elevations, because there are colder temps
Oreographic lift is strongest when - correct answer winds are
perpendicular to mountains
Wind exposed location - correct answer - mountain peaks and ridgetops
where there is less landmass or ground to slow down wind by friction
- wind is worse higher up in the troposphere on mountains and ridges than
on the ground because of friction
What is the exception to a ridge being a windexposed area - correct
answer if you are on a ridge surrounded by other ridges, the friction and
turbulence might slow down the winds somewhat but still, it will be stronger
than winds below
What is the most extreme example of a wind exposed location - correct
answer volcanic peaks because they rise so far above surrounding terrain
What is the venturi/bernoulli effect - correct answer - when air/wind flow
over a mountain goes through convergence and accelerates/speeds up
