LAKE EFFECT PRACTICE

A) lake-effect snowstormB) tornadoC) warm, sunny weatherD) hurricane

1. In winter, a cold, dry air mass from Canada movesacross Lake Ontario. The air over the lake is warmerand more humid than the air over the land. Whichweather condition is most likely to occur as the airmass reaches Oswego?

A) in the path of prevailing winds from LakeOntario

B) in the Northern HemisphereC) near the Atlantic OceanD) west of the Hudson-Mohawk Lowlands

2. The heavy lake-effect snowfalls in the Tug HillPlateau region occur primarily because the plateau islocated

LAKE EFFECT PRACTICE

Base your answers to questions 3 through 6 on "the magazine article and diagram below.

Lake-Effect Snow

During the cold months of the year, the words "lake effect" are very much a part of the weatherpicture in many locations in New York State. Snow created by the lake effect may represent morethan half the season's snowfall in some areas. In order for heavy lake-effect snow to develop, the temperature of the water at the surface ofthe lake must be higher than the temperature of the air flowing over the water. The higher thewater temperature and the lower the air temperature, the greater the potential for lake-effect snow. A lake-effect storm begins when air flowing across the lake is warmed as it comes in closecontact with the water. The warmed air rises and takes moisture along with it. This moisture,which is water vapor from the lake, is turned into clouds as it encounters much colder air above.When the clouds reach the shore of the lake, they deposit their snow on nearby land. A typicallake-effect storm is illustrated in the diagram below. The area most likely to receive snow from a lake is called a "snowbelt." Lake Ontario'ssnowbelt includes the counties along the eastern and southeastern ends of the lake. Because thelake runs lengthwise from west to east, the prevailing westerly winds are able to gather themaximum amount of moisture as they flow across the entire length of the lake. There can belake-effect snowfall anywhere around the lake, but the heaviest and most frequent snowfalls occurnear the eastern shore. In parts of the snowbelt, the lake effect combines with a phenomenon known as orographiclifting to produce some very heavy snowfalls. After cold air has streamed over the length of LakeOntario, it moves inland and is forced to climb the slopes of the Tug Hill Plateau and theAdirondack Mountains, resulting in very heavy snowfall.

"3. State the relationship that must exist between water temperature and air temperature for lake-effect

snow to develop.

4. State why locations east and southeast of Lake Ontario are more likely to receive lake-effect snow thanare locations west of the lake.

5. State the name of the New York State landscape region that includes location A shown in the diagram.

LAKE EFFECT PRACTICE

6. State why very heavy snowfall occurs in the Tug Hill Plateau region.

7. Base your answer to the following question on on the passage and map below. The map shows theaverage yearly precipitation in New York State measured in inches.

Landscapes and Precipitation

Moisture from the Gulf of Mexico and the Atlantic Ocean is carried to New York State by stormsystems and air currents. Rain and snowfall amounts vary by region. Heavy snow belts are locatednear Lake Erie and Lake Ontario as well as in the plateau regions of eastern and northern NewYork State. Long Island and New York City usually experience lighter snowfalls. Snowfallamounts are converted to inches of water to determine yearly precipitation.

On the map below, draw one arrow to show the path that air travels to produce heavy lake-effectsnowfall in Oswego, New York.

LAKE EFFECT PRACTICE

A)

B)

C)

D)

8. Which cross section below best represents the conditions that cause early winter lake-effectsnowstorms in New York State?

LAKE EFFECT PRACTICE

9. Base your answer to the following question on the map below, which shows the snowfall from the fallof 1976 through the spring of 1977, measured in inches, for most of New York State. The 200-inchsnowfall isolines are shown on the map.

Identify one factor that contributes to the high snowfall amounts at locations on the eastern side of both Lake Erie and Lake Ontario.

A) New York City B) UticaC) Plattsburgh D) Watertown

10. On the map below, dark-gray areas represent regionsof lake-effect snow on a December day.

Which New York State location appears to beexperiencing a lake-effect snowstorm?

LAKE EFFECT PRACTICE

11. Base your answer to the following question on the map below, which shows a portion of New YorkState and Canada. The arrows represent the direction of the wind blowing over Lake Ontario forseveral days early one winter.

Explain why Oswego, New York, usually gets more snow than Toronto, Canada, when the wind isblowing in the direction shown on the map.

LAKE EFFECT PRACTICE

Base your answers to questions 12 through 15 on the reading passage about lake-effect snow and theradar image map below, and on your knowledge of Earth science. The radar map shows areas wheresnowfall was occurring. The whitest area indicates where snowfall was heaviest.

Lake-Effect Snow

In late fall, cold air originating in Canada and then moving over the Great Lakes oftenproduces lake-effect snow in New York State. When the cold air mass moves across large areas of warmer lake water, water vapor enters thecold air. When this moist air moves over the cooler land, the moisture comes out of theatmosphere as snow. The effect is enhanced when the air that flows off the lake is forced overhigher land elevations. The areas affected by lake-effect snow can receive many inches of snowper hour. As the lakes gradually freeze, the ability to produce lake-effect snow decreases.

A) mT B) mP C) cT D) cP

12. What is the most likely two-letter air mass symbol for an air mass from Canada that produceslake-effect snow in New York State?

LAKE EFFECT PRACTICE

A)

B)

C)

D)

13. Which map shows the most likely direction that winds were moving across Lake Ontario to producethis lake-effect snow?

LAKE EFFECT PRACTICE

A) air contracts as it sinks air warms to the dewpoint water evaporatesB) air expands as it rises air warms to the dewpoint water vapor condensesC) air contracts as it sinks air cools to the dewpoint water evaporatesD) air expands as it rises air cools to the dewpoint water vapor condense

14. Which list indicates the correct sequence in the formation of a lake-effect snow cloud?

A) The ice prevents liquid water from evaporating into the atmosphere.B) The lower temperature of ice makes liquid water condense at a slower rate.C) More water is available to evaporate.D) Ice speeds up the air moving above it, so less water can evaporate.

15. Which statement best explains why lake-effect snow decreases when lakes freeze gradually?

A) northeast B) northwest C) southeast D) southwest

16. The map below shows the amount of snowfall, in inches, produced by a lake-effect snowstorm incentral New York State.

The wind that produced this snowfall pattern most likely came from the

LAKE EFFECT PRACTICE

A) cold air moves to the east over warmer lakewater

B) cold air moves to the west over warmer landregions

C) warm air moves to the east over colder lakewater

D) warm air moves to the west over colder landregions

17. The striped areas on the map below show regionsalong the Great Lakes that often receive largeamounts of snowfall due to lake-effect storms.

These storms generally develop when

A) cold air moves to the east over warmer lake waterB) cold air moves to the west over warmer land regionsC) warm air moves to the east over colder lake waterD) warm air moves to the west over colder land regions

18. The striped areas on the map below show regions along the Great Lakes that often receive largeamounts of snowfall due to lake-effect storms.

These storms generally develop when

LAKE EFFECT PRACTICE

Base your answers to questions 19 through 21 on the passage and the graph below and on yourknowledge of Earth science.

Great Lake Effects

The Great Lakes influence the weather and climate of nearby land regions at all times of theyear. Much of this lake effect is determined by the relative temperatures of surface lake watercompared to the surface air temperatures over those land areas. The graph below shows theaverage monthly temperature of the surface water of Lake Erie and the surface air temperature atBuffalo, New York. In an average year, four lake-effect seasons are experienced. When surface lake temperaturesare colder than surface air temperatures, a stable season occurs. The cooler lake waters suppresscloud development and reduce the strength of rainstorms. As a result, late spring and earlysummer in the Buffalo region tends to be very sunny. A season of lake-effect rains follows. August is usually a time of heavy nighttime rains, andmuch of the rainy season is marked by heavy, localized rainstorms downwind from the lake.Gradually, during late October, lake-effect rains are replaced by snows. Generally, the longer thetime the wind travels over the lake, the heavier the lake effect becomes in Buffalo. Finally, conditions stabilize again, as the relatively shallow Lake Erie freezes over, usually nearthe end of January. Very few lake-effect storms occur during this time period.

19. The passage states, "The cooler lake waters suppress cloud development ... " because the water coolsthe air above its surface. Explain why this cool air above the lake surface reduces the amount ofcloud development.

20. Identify one weather variable that determines whether Buffalo receives rain or snow from alake-effect storm in October.

21. Explain why the Buffalo surface air temperatures increase faster and earlier in the year than do thesurface water temperatures of Lake Erie.