Severe and Hazardous Weather

What happens to air as it rises?

-It expands, cools, and the RH increases It contracts, warms, and the RH decreases It contracts, cools, and the RH decreases It expands, warms, and the RH increases

What are the benefits of using numerical models for tornado prediction? Select all that are correct.

-It helps us understand why certain supercells produce tornadoes and others don't. It can predict where specifc tornadoes will form and travel 48 hours in advance. -It gives you a probability of a tornado forming in different locations.

Why is strong heating of the ground by the Sun associated with thunderstorms?

-It leads to greater instability. It reduces the relative humidity. It reduces the dewpoint. It increases the wind speed.

Why is doppler radar our most effective tool for tornado detection? Select all correct answers.

-It shows the speed a storm is traveling. It shows whether a tornado has touched down or not. It shows the rotation of a tornado. -It shows the direction a storm is traveling. -It shows rotation of a supercell thunderstorm.

Which of the following are true about the enhanced Fujita (EF) scale? Select all that are correct.

-Less than 1% of tornadoes are EF-5. Tornadoes are rated by their average wind speed. You are likely to survive on the 2nd floor of a home that gets struck by an EF-5 tornado. -Tornadoes are rated by the damage they do. -An EF-1 can overturn a mobile home.

What are some of the initial signs that hypothermia is just beginning?

-Lethargy and intense shivering Dilated pupils Entering a coma Hyperactivity

Which of these is common to both cold and warm fronts?

-Lifting warm air over cold. Decreasing precipitation rates. Steady pressure readings. Light to calm winds

The Great Salt Lake is oriented NW to SE (aka the long axis of the lake extends from SLC to the NW). Which of the following wind directions would provide the longest residence time of air over the Great Salt Lake?

-NW There would be no difference in residence time with different wind directions NE SW

Why was the May 2011 Joplin tornado so deadly? Select all correct answers.

-Not everyone in the area had access to underground shelters. -It traveled through a populated area. It traveled through Joplin around midnight. It was rated EF-2. -It was very strong tornado

What direction does the geostrophic wind blow?

-Parallel to the isobars, with low pressure on the left in the northern hemisphere. Parallel to the coriolis effect. Directly toward low pressure. From west to east.

Which of the following are actions you should take BEFORE a severe winter weather event? Select all that are correct.

-Purchase a NOAA weather radio. -Update your emergency kit. Look for signs of hypothermia. Stay indoors and don't go outside. - Winterize your vehicle

While backcountry skiing can be dangerous, it also can be done very safely with little risk. What should people do to stay safe in the backcountry? Select all that are correct.

-Read the avalanche forecast. -Constantly assess the safety of the current conditions and travel route. -Get trained in avalanche science and safety. -Recognize group dynamics and stoke. Let the most experienced in the group make all decisions. Only ski in the backcountry alone so you are in charge of all decisions. -Stay on low angle and treed slopes if conditions are dangerous.

What direction do hurricanes spin in the northern and southern hemispheres? Select all that are correct.

-SH: Clockwise NH: Clockwise SH: Counterclockwise -NH: Counterclockwise

What are the four components you need to have an avalanche? Select all four.

-Slab of snow. -Weak layer of snow. -Steep slope. Trees on the slope. - Trigger.

Which of the following weather changes was most likely from a cold front passing?

-Temperatures in the 60s and winds from the south, then temperatures in the 40s and winds from the northwest. Temperatures in the 50s and winds from the southeast, then temperatures in the 60s and winds from the southwest. Temperatures in the 60s and winds from the south, then temperatures in the 60s and winds from the southwest. Temperatures in the 50s and winds from the southeast, then temperatures in the 40s and winds from the southwest.

Why are thunderstorms most likely to occur in the afternoon and early evening?

-The atmosphere is most unstable at that time. It takes all day for them to mature. Upper level winds are too fast at night and in the morning. Water vapor content is too low at night.

Why does occlusion lead to the demise of a mid-latitude cyclone?

-The horizontal temperature gradient at the surface has been eliminated. The cold front stops progressing during occlusion. The cold cP air mass driving the cyclone has warmed intensely.

What is differential heating and what causes it?

-The sun heats some parts of our planet more than others, leading to temperature differences. Different temperatures of air reduce the pressure gradients to zero. The sun is sluggish and only heats a very small percentage of the earth's surface. Pressure gradients block the rays of the sun leading to cooling.

For lake effect snow, what large scale weather pattern is needed?

-Very cold air moving across the lake. Very warm air moving across the lake. Very dry air moving across the lake. Large scale sinking motion in the region.

Which of the following is NOT a condition needed for hurricane formation?

-Very shallow layer of warm surface water, less than 10 meters deep. Weak vertical wind shear. Sea surface temperatures greater than 80 degrees F. At least 5 degrees north of south of the equator.

What tools do meteorologists have now, that they did not have 50 years ago? Select all that are correct.

-Weather Satellites - Powerful Computers -Doppler Radar Visual Observations (storm spotters) Surface Weather Stations

How do meteorologists collect weather measurements? Select all that are correct.

-Weather buoys. - Weather satellites. -Surface weather stations. -Weather drones (e.g. aerosondes). -Weather balloons (radiosondes).

What is a cutoff low?

-When the jetstream wraps into a completely closed vortex aloft. When a low is only present at the surface and not aloft. When cold and warm air separate apart. The cyclone spins so fast that the fronts disappear.

A warm front is said to exist when

-advancing warm air overrides retreating cold air. warm and cold air meet. moving cold air overrides warmer air. warm air pushes underneath cold air

The gust front occurs

-at the leading edge of a thunderstorm downdraft. on the lee shore of the Great Lakes. during the development of thunderstorm clouds. near the anvil part of a thunderstorm cloud

From the Rockies westward to the Pacific, what are the primary controls on snowfall?

-elevation and mountains cloud seeding and hydropower lakes and airmasses latitude and temperature

What is the force behind dynamically driven mountain wind storms?

-pressure gradient force frictional force radiative cooling coriolis effect

Why are rotors a hazard for airplanes?

-they produce clear air turbulence they create freezing rain they produce very large severe thunderstorms they cause engines to seize

What causes the winds of a hurricane to be so fast?

-very strong pressure gradient force strong Coriolis effect strong tidal effects coupling with the jet stream

The lifting of air and the resulting formation of clouds and rain is more gentle (gradual) for a

cold front. occluded front. mesocyclone. -warm front.

Thunderstorms form when ____________, humid air rises in a(n) _____________ environment.

cold; stable -warm; unstable warm; stable cold; unstable

What is the driving force for katabatic winds down an ice sheet?

coriolis effect adiabatic cooling frictional force -gravity

The eye wall of a hurricane

has the lightest precipitation. has the highest barometric pressure. -has the greatest wind speeds. lies at the hurricane's outer edge.

What general circulation wind belt is the place of origin for hurricanes?

horse latitudes doldrums midlatitude westerlies -tropical easterly trades

Which of the following can diminish the intensity of a hurricane?

intense thunderstorms frequent lightning moving over warmer water -moving over land

Why is freezing rain ice considered the "toughest ice on earth"?

it has a different chemical composition than regular ice. It is very reflective and blinds people once the sun comes out. - It freezes very quickly and contains very little air. It has a melting point above 32 degrees F

Why are Chinook winds often warmer than the upstream air?

land cover changes warm air advection adiabatic cooling due to rising air -latent heating and loss of moisture

A large percentage of structural damage and coastal flooding from tropical storms and hurricanes can be attributed to

lightning. tornadoes. strong winds. -storm surge.

The video describes two airmasses that come together over "tornado alley" in the spring. One is from the northern Pacific Ocean and the other is from the Gulf of Mexico. What are the categories of these two airmasses?

mP and cP cT and mT - mP and mT cP and cT

A GPS dropwindsonde is used for

measure temperatures in the outflow of a hurricane. forecasting precipitation associated with the hurricane's eye wall. locating and measuring the diameter of the hurricane's eye at the surface. - measuring wind speeds throughout every level of a hurricane, determining intensity.

A dryline causes uplift to occur because

the intruding air mass is colder and more dense than the lifted air mass. the intruding air mass warmer and less dense than the lifted air mass. the lifted air mass is dryer and more dense than the intruding air mass. -the lifted air mass is moister and less dense than the intruding air mass.

If you want to ski in the backcountry on "High" or "Considerable" danger day, what types of areas are the safest to ski?

A rocky area. - A low angle slope with trees (and no steep slopes above it). A steep slope that has many trees. Avalanche terrain.

How does temperature change as you go up through the atmosphere during freezing rain?

Above freezing at surface, below freezing in the middle, and warm up high. -Below freezing at surface, above freezing in the middle, and cold up high. The temperature is constant as you go up. Warm at the surface and cold up high.

What is needed for a freezing rain event to become an "ice storm"?

Freezing rain is accompanied by more than 4 feet of snow. -Freezing rain conditions persist for many days. Freezing rain melts rapidly. All trees collapse due to the weight of ice.

Where does the moisture from the Monsoon come from?

From the dying of upstream thunderstorms. It descends from the upper atmosphere. -Water evaporated from the ocean and transported inland. From large rivers throughout the region.

What actions should be taken if the location you are in is under a tornado watch?

Go outside to watch the tornado. -Keep alert of the weather and make sure you have a safe place to shelter if tornadoes do occur. Watch out for debris from a distant tornado. Immediately seek shelter underground or in a ground floor interior room.

What two forces are in balance when you have a geostrphic wind? Select the two forces.

Gravitational force -Coriolis effect Frictional force -Pressure gradient force

What is a common reason that people who are struck by lightning are able to survive?

If you are standing on the ground, lightning will just pass through you, and won't harm you. -The electricity passes over the surface of their skin. The lightning stops, but then restarts their heart. The lightning hits the brain, which doesn't not harm them.

What is the most important thing you can do if you live in a location that has severe weather?

Ignore watches, warnings, and evacuations. Always lock you doors and windows. Put up a weather station at your house. -Be prepared for the effects of severe weather.

What is surface hoar and when does it form? Why does it help cause avalanches?

It is a rain crust that has aged. It provides a weak layer. It is a thick layer of dense snow. It is a slab. -Crystalline feathery frost that forms on cold clear nights. It provides a weak layer. A crust that forms from warm days. It is a slippery layer.

Why does vortex stretching contribute to tornado formation?

It leads to hail formation. It pulls the tornado back into the storm. - It narrows and increases the rotating winds. It widens and slows down the rotation.

Why is vertical wind shear important for tornado formation?

It makes the updraft and downdraft form in the same location at the same time. It destroys the thunderstorm within one or two hours. It prevents hail formation. - It creates horizontal rotation.

Why is Doppler radar useful for tornado forecasting and warning?

It shows which clouds contain dust or smoke. It can see the tornado touching the ground. It detects the sound of tornadoes ripping apart trees and houses. -It can detect tornado vortex signatures.

How does the form of precipitation change as it falls through the atmosphere during freezing rain?

It starts as rain and freezes to snow. -Starts as snow, melts to rain, then freezes on contact with the surface. It starts as hail that melts into rain. It starts as snow, melts to rain, then freezes into ice pellets.

What important feature does Doppler add to radar measurements?

It tells you the intensity of the rain. It measures the electrification of the storm. It tells you whether hail is present. -It tells you whether the raindrops are moving toward or away from the radar.

What actions should be taken if the location you are in is under a tornado warning?

Keep and eye on the weather and make sure you have a shelter if a tornado does occur. Go outside and watch the tornado. Run outside and go door to door warning others that a tornado is coming. - Immediately seek shelter underground or in a ground level interior room.

Which of the following is a measure of a parcel's positive buoyancy above the level of free convection, as calculated from stuve diagram?

LFC BAMEX -CAPE BWER

Imagine there are two lake in upstate New York. It is December, and lake A has frozen over, but lake B still has mostly open water. Which lake is more likely to produce lake effect during this month?

Lake A Lake A and B are equally likely to produce lake effect -Lake B Neither lake will produce lake effect

Where do the thunderstorms in hurricanes draw their heat from?

Large changes in wind speed as you go up through the atmosphere. Cold land temperatures. Warm air in the upper atmosphere. -Warm ocean water.

What causes the dissipating stage of a thunderstorm?

Loss of radiant energy from the cloud top. Converging winds aloft. -The spreading downdraft cuts off air inflow. Release of latent heat within the cloud.

In the northern hemisphere what is the direction of air motion around high and low pressure systems? Select all that are correct.

Low pressure: Clockwise High pressure: Counterclockwise -High pressure: Clockwise -Low pressure: Counterclockwise

Why are power outages likely during an ice storm?

People need to heat their homes more and it overload the power stations. Cell phone towers get overloaded with calls and explode causing massive fires. Ice short circuits the power lines causing blowouts. -The ice is so heavy it causes trees and power poles to collapse.

How does La Nina affect tornado activity in the United States?

Shuts off the transport of warm moist air from the Gulf of Mexico. -Creates a strong jet stream across the United States. Reduces the rotation of winds. Makes the air in tornado alley much less humid.

When friction is in play, how is wind speed AND direction different than with the geostrophic wind? Select all that are correct.

Speed is increased. -Winds veer across the isobars toward low pressure. Winds veer across the isobars toward high pressure. -Speed is reduced.

What are the three basic things you need to have weather? Select all that are correct.

Temperatures below freezing -Air -Moisture -Heat

What condition is present during a lake effect snowstorm?

The air temperature is warmer than the lake temperature. - The lake temperature is warmer than the air temperature. The air temperature and the lake temperature are the same.

Why are thunderstorms most common in the summer?

The air tends to sink rapidly - More heat is available There are intense surges of cold air The relative humidity is the highest

How does Doug Chabot, who issued the Gallatin National Forest Avalanche Advisory, characterize the avalanche danger on Jan. 1?

The avalanche danger was "Considerable." The avalanche danger was "Extreme." The avalanche danger was "Low." -The avalanche danger was "High" and there was an Avalanche Warning.

What is Snow Water Equivalent?

The difference in the amount of snow falling in a valley and in the mountains. The density of snow. - The depth of water that would be obtained if snow is melted. The vertical motion in a storm.

What is the pressure gradient force?

The force that keeps our atmosphere from flying off into space. A force caused by friction. -Force caused by the change in pressure divided by a change in distance. An apparent force caused by the rotation of earth.

The more violent nature of weather produced by a cold front can be attributed to which two factors?

The gradual slope and slow forward motion of the front. The gradual slope and fast forward motion of the front. The steep slope and slow forward motion of the front. -The steep slope and fast forward motion of the front.

Why was it difficult and dangerous for a helicopter to fly in to rescue the injured skier?

The hut was on private land and they were not allowed to land there. The pilots were not used to flying in mountainous terrain. -The weather was terrible and the ceiling (cloud height) was low.

Which of the following is NOT needed to have a tornado?

The rotating winds must touch the ground. Violently rotating winds. - A funnel cloud that touches the ground.

What was the "human factor" that contributed to this avalanche accident?

The skier created more surface hoar from skiing on the slope. -They kept going higher on the slope and into more dangerous terrain. The stoke of the day. The skiers were not educated in avalanches. The skiers didn't know there was avalanche danger on the slope they were skiing.

What is "lead time"?

The speed of a tornado. The amount of time a tornado is on the ground. The time it takes to get into an underground shelter. -The time between a tornado warning being issued for a location and a tornado striking the location.

Why don't hurricanes develop on or near the Equator?

The water is too warm to allow storm development. The ITCZ inhibits the growth of thunderstorms. Hurricanes DO develop on the equator, very frequently. -The Coriolis effect is too weak there to create rotation.

Which of the following will be a likely effect of future climate change on mountain snows?

There will be more water available when water demand is highest. Snow will fall at lower altitudes with rain at higher altitudes. The frequency and intensity of extratopical cyclones in autumn and spring will be increased. -Later first snow and earlier snowmelt

What is the most useful meteorological measurement for forecasting freezing precipitation?

Wind profiler Visible sattelite Surface weather station -Radiosonde soundings

What is used to rank a tornado on the Fujita scale?

Wind speed. Storm height. -Damage assessments. Radar reflectivity.

What is La Nina?

Wind that change direction with height. -Cold sea-surface temperatures off the coast of Peru. Warm sea-surface temperatures off the coast of Peru. A time of year when tornadoes are very common.

What factors contribute to flash flooding in mountainous regions? Select all that are correct.

-A bowl shaped valley with everything draining to one narrow spot. The high permeability of the soils. - Heavy rain over one valley for an extended period of time. -Moist air rising up and over mountain tops.

If you were looking at a weather map, how would you identify a location with a very strong pressure gradient force?

-A location where the isobars are closely packed together. A location where the isobars are widely spread apart. A location where the temperatures are very warm. A location where the temperatures are very cold.

What is a mesocyclone?

-A rotating updraft in a supercell thunderstorm. A very large tornado. An index for wind shear. A funnel cloud.

How do experts think we can prevent future deaths tornado deaths? Select all that are correct.

-An improved doppler radar system. -Revise warnings and alerts so residents are more likely to shelter immediately. -Enhance building codes. -Increase lead time. -Tornado education for residents.

In the advisory, what does Doug say are the reasons for this level of avalanche danger? Select all that are correct.

-Both natural and human triggered avalanches are likely. It has warmed up rapidly in the past 24 hours. -Areas of unstable snow exist. -New snow has been deposited on an extremely weak snowpack.

Which of the following are actions you should take DURING a severe winter weather event? Select all that are correct.

-Conserve fuel by reducing the temperature of your home or closing of rooms. Make a communications plan. -Stay indoors during the storm. -Keep dry and warm. -Look for signs of hypothermia.

What are some of the ingredients that produce tornadic storms (supercells) in the midwestern U.S.? Select all that are correct.

-Different directions of wind at the bottom and top create rotation in the storm. -The jetstream come down from Canada at high levels. -Strong updrafts are able to burst through the lid of dry air. -Transport of warm moist air at the surface from the Gulf of Mexico. -Dry air from the southwest is present at mid-levels. -The sun heats the ground, causing surface air to rise.

How is the atmosphere different when sleet (ice pellets) is falling compared to snow?

-For sleet there is a warm layer somewhere in the middle of the troposphere. During sleet the whole cloud is always above freezing. During sleet the air is much colder all the way up. During sleet the surface air is above freezing.

What does the survivor say he would change if he were in the same situation again?

-If one member disagreed with the decision to ski a slope they would not ski it. He wouldn't ski with the same group of people. He would always have a helicopter on call for rescues. He would not ski in the backcountry ever again.

How many avalanche paths effect the Little Cottonwood Canyon road in the Wasatch mountain of Utah?

2 0 7,000 - 42

What was Hurricane Pam? Select all that are correct

A Hurricane that caused many deaths. - It took place about a year before Hurricane Katrina. -A disaster training exercise. A Hurricane that made landfall on the Gulf Coast.

What is supercooled water?

A cloud that changes from water to ice rapidly -Liquid water that is below 0 degrees C Water that cools off very rapidly Ice crystals that grow by deposition

What does the term mesocyclone refer to in reference to a tornado?

A high altitude tornado. A false alarm tornado warming. A very large tornado. -The rotation of the updraft in the parent thunderstorm.

Why were the May 2011 Oklahoma tornadoes much less deadly than the April 2011 Joplin tornado? Select all that are correct.

All of the homes in Oklahoma are built to withstand EF-3 tornadoes. -Some residents of Oklahoma have tornado safe rooms. The Joplin tornado was stronger than any that hit in Oklahoma. -The Oklahoma tornadoes missed major population centers. -Tornado awareness is higher in Oklahoma than it is in Missouri.

When or where is it important to take friction into account when determining wind speed and direction?

Always. - Close to the ground. High in the atmosphre. When wind speeds are very fast.

Why do we have a coriolis effect on the planet Earth?

Because we have merry-go-rounds. -Because the earth rotates. Because we have land and oceans. Because the earth is tilted

Which of the following vertical profiles will give you freezing rain? [From bottom to top]

Deep cold layer, Cold aloft Deep warm layer, Cold aloft Deep cold layer, Shallow warm layer, Cold aloft -Shallow cold layer, Deep warm layer, Cold aloft

When a shore parallel band is forming in the center of a lake, what process is happening at the surface over the center of the lake?

Divergence Sublimation Sinking air -Convergence

Katrina first formed as a tropical wave off of what continent?

Europe South America Asia -Africa

A frontal squall line is usually associated with what larger scale weather system?

Extratropical cyclone and associated warm front. -An extratropical cyclone and associated cold front. A hurricane and associated cold front. A tsunami and associated wave front