CONTEST STATUS - Updated: SUN...20-JUL-14 @ 7:35 PM EDT

Winter '14 / '15 - Snowfall Forecast Contests

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16th Annual 'Regular Season'

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14th Annual 'Season-total'

Wednesday, January 19, 2011

Winter '10 / '11 - Northeastern Snowfall Impact Scale - Return Periods

The heavy snowfall of late December scored a 4.92 on the Northeastern Snowfall Impact Scale (NESIS).  It ranked 59th out of 76 events.

How often can a storm of this impact be expected to affect the NE?

Plotting the Gumbel distribution curve for the 76 NESIS events...we can estimate the return period of a 4.92 magnitude snow storm as 3.72 years.

What about the estimated return periods for the 'Top-5' NESIS storms?
Was the March-93 'Superstorm' really the 'Storm of the Century?' The Great Blizzard of JAN-96...ranked 2nd highest NESIS...was another memorable storm of the late 20th century.

How often can storms of such extreme impact be expected?

'Top-5' NESIS Events and Index...
12/14-MAR-93: 13.20
6/8-JAN-96: 11.78
2/5-MAR-60: 8.77
15/18-FEB-03: 7.50
2/5-FEB-61: 7.06

Gumbel distribution for 76 NESIS events
Return period...in years...for the 'Top-5' NESIS events...
12/14-MAR-93: 340
6/8-JAN-96: 153
2/5-MAR-60: 28.5
6/7-FEB-03: 14.2
2/5-FEB-61: 11.2

The return period for the MAR-93 Superstorm is more than twice as long as its nearest neighbor...the Great Blizzard of JAN-96.  Consider yourself lucky to have been alive when these genuinely historic storms occurred b/c it'll likely be a long...long time before a snow storm will have such a severe impact on the NE again.

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