Lake Vermilion Ice-Out Equations

Legend:

Iceout Day--The day the ice will go out based on the "weather data used"

in the equation.

Dec.TH - The actual average high temperature (TH) in Fahrenheit for Dec.

of 2009.

Dec.TL - The actual average low temperature (TL) in Fahrenheit for Dec.

for 2009.

Dec.S - The actual snow (S) fall total in inches for Dec. for 2009.

Jan. to May-The actual average monthly high/low temperatures (TH, TL)

and snow (S) fall totals in inches in 2010. You may use average daily

(not a full month) weather data for months of April/May.

Use iceoutdatabase10 to make an educated estimate of future weather when

actual data is not available.

Note Example.

WEATHER
DATA USED

CHANCE OF
PREDICTING
ICEOUT DAY

December (only)

27.7 %

Iceout Day =

110.06

+ .276x(DecTH)

- .119x(DecTL)

+ .308x(DecS)

January (only)

39.8 %

Iceout Day =

114.11

+ .061x(JanTH)

- .394x(JanTL)

+ .049x(JanS)

Dec. + Jan.

42.6 %

Iceout Day =

112.42

- .125x(DecTH)

+ .213x(DecTL)

+ .114x(DecS)

+ .207x(JanTH)

- .510x(JanTL)

+ .026x(JanS)

Febuary (only)

49.1 %

Iceout Day =

136.13

- .696x(FebTH)

+ .005x(FebTL)

- .037x(FebS)

Dec., Jan., Feb.

59.4 %

Iceout Day =

128.54

- .075x(DecTH)

+ .185x(DecTL)

+ .104x(DecS)

+ .385x(JanTH)

- .544x(JanTL)

+ .032x(JanS)

- .834x(FebTH)

+ .215x(FebTL)

- .009x(FebS)

March (only)

49.1 %

Iceout Day =

150.8

- .997x(MarTH)

+ .278x(MarTL)

+ .148x(MarS)

Dec., Jan.,
Feb. & March

68.1 %

Iceout Day =

150.04

+ .054x(DecTH)
- .825x(MarTH)

+ .074x(DecTL)
+ .225x(MarTL)

+ .067x(DecS)
- .108x(MarS)

+ .173x(JanTH)

- .386x(JanTL)

- .058x(JanS)

- .433x(FebTH)

- .065x(FebTL)

- .017x(FebS)

April (only)

70.9 %

Iceout Day =

165.79

- 1.03x(AprTH)

+ .161x(AprTL)

+ .243x(AprS)

Dec., Jan., Feb.,
Mar. & April

87.5 %

Iceout Day =

174.96

- .068x(DecTH)
- .347x(MarTH)

- .020x(DecTL)
- .094x(MarTL)

- .021x(DecS)
+ .146x(MarS)

- .175x(JanTH)
- .757x(AprTH)

- .008x(JanTL)
+ .100x(AprTL)

+ .046x(JanS)
+ .341x(AprS)

- .310x(FebTH)

+ .027x(FebTL)

+ .052xFebS)

Dec., Jan., Feb.,
Mar., Apr. & May

90.5 %

Iceout Day =

157.35

- .007x(DecS)
+ .082x(MarS)

- .152x(JanTH)
- .624x(AprTH)

- .012x(JanTL)
+ .030x(AprTL)

+ .027x(JanS)
+ .219x(AprS)

- .155x(FebTH)
- .016x(MayTH)

- .057x(FebTL)
+ 152(MayTL)

- .001x(FebS)
+ 3.18(MayS)

- .219x(MarTH)

- .075x(MarTL)

EXAMPLE
Using Dec, Jan,
Feb. weather
data.

59.3 %

Iceout Day =

128.54
128.54
128.54

- .075x(DecTH)
- .075x20.56
- 1.54

+ .185x(DecTL)
+ .185x .621
+ .115

+ .104x(DecS)
+ .104x11.78
+ 1.23

+ .385x(JanTH)
+ .385x15.85
+ 6.10

- .544x(JanTL)
- .544x(-6.90)
+ 3.75

+ .032x(JanS)
+ .032x12.81
+ .410

- .834x(FebTH)
- .834x22.02
- 18.36

+ .215x(FebTL)
+ .215x(-3.17)
- .682

- .009x(FebS)
- .009x9.27
- .083

Iceout Day = 119.456 - (April 10 = 100) so 119 = April 29.
April 29th is your Ice=Out entry with a 59.4% chance of being correct!
GOOD LUCK! Iceman '10