How does the Northeast Snowfall Impact Scale Work?

The Northeast Snowfall Impact Scale (NESIS) NESIS has five categories: Extreme, Crippling, Major, Significant, and Notable. NESIS scores are a function of the area affected by the snowstorm, the amount of snow, and the number of people living in the path of the storm.

What is a NESIS value?

It indicates the relative impact of the snowstorm on people, and is not a measure of a purely physical phenomenon like wind speed. An “NESIS value” is calculated from the area covered, the depth of the snowfall, the population of the area covered, and two constants based on historical experience with large snowstorms.

What scale is used to measure the intensity of a blizzard?

A blizzard is one type of storm that has no scale in which to measure its intensity. A blizzard’s strength is measured by an estimate based off of total snowfall and wind speeds.

How high was the snow in the blizzard of 78?

Boston received a record-breaking 27.1 inches (69 cm) of snow; Providence also broke a record, with 27.6 inches (70 cm) of snow; Atlantic City broke an all-time storm accumulation, with 20.1 inches (51 cm), two Philadelphia suburban towns in Chester County received 20.2 inches (51 cm) while the City of Philadelphia …

What are the 5 categories of blizzards?

The five categories are Extreme, Crippling, Major, Significant, and Notable. The NESIS scale differs from the hurricane and tornado ranking scales in that it uses the number of people affected to assign its ranking.

Do blizzards have a rating system?

The scale was developed by meteorologists Paul Kocin and Louis Uccellini, and ranks snowstorms from Category 1 (“notable”) to Category 5 (“extreme”). Only two historical blizzards, the 1993 Storm of the Century and the North American blizzard of 1996 are rated in the 5 “extreme” category.

How can we reduce the impact of blizzards?

Bring a winter storm kit (chains, booster cables, shovel, blankets, extra clothing, food, water, or a cell phone if you have one). Reduce speeds and allow extra distance for braking on slick roadways. Keep away from downed power lines. If you become stranded, turn on the emergency flashers or raise the hood.

How do meteorologists measure snowfall?

A snow gauge is a type of instrument used by meteorologists and hydrologists to gather and measure the amount of solid precipitation (as opposed to liquid precipitation that is measured by a rain gauge) over a set period of time.

How do meteorologists categorize the severity of a blizzard?

In order for meteorologists to classify a winter storm as a snowstorm, the air temperature high in the atmosphere and near the ground must be below 0°C (32°F). There also needs to be enough water vapor in the air to form snowflake crystals.

What is a Category 5 snowstorm?

A Category 5 Extreme ranking is indicated by a numerical score of 18 or higher on the scale. Out of the over 500 historical storms assessed since 1900, only twenty-six storms have been given a Category 5 ranking. The highest ranking storm on the list is the Great Blizzard of 1978 which scored a value of 39.07.

What is the Nesis scale?

The Northeast Snowfall Impact Scale (NESIS) developed by Paul Kocin and Louis Uccellini of the National Weather Service (Kocin and Uccellini, 2004) characterizes and ranks high-impact Northeast snowstorms. These storms have large areas of 10 inch snowfall accumulations and greater.

What is the impact of a blizzard on NESIS?

A theoretical blizzard may only impact enough people with enough snow to rate a category 2 on NESIS, but bring winds of over 70 MPH, paralyzing the region for days as 5-10 foot drifts and windblown debris are removed. Also, NESIS specifically provides for the storm’s impact to the entire population of the affected area.

What is Nesis and why does it matter?

The scale also allows for meteorologists to predict how long airport delays caused snowstorms will last and when things will become normal afterward. According to Uccellini, NESIS will be used to reevaluate recent snowstorms and measure their impact and not as forecasts such as the ones that are created for hurricanes.

What is the RSI of a snowstorm?

Regional Snowfall Index (RSI) The Northeast Snowfall Impact Scale (NESIS) Overview. While the Fujita and Saffir-Simpson Scales characterize tornadoes and hurricanes respectively, there is no widely used scale to classify snowstorms.