great info on wave heights

[aniceguy]

copied from another site

 

 

Below are threat level / wave height definitions from the NOAA site.

 

 

Marine Wind & Sea Threat Level

Threat Level Descriptions

 

Extreme

"An Extreme Threat to Life and Property Aboard Marine Vessels, Especially Small Craft, from Marine Winds/Seas."

Storm-force prevailing winds with extreme combined seas. Sustained winds of 48 knots or greater (Beaufort Scale 10+). Winds of this strength, combined with a long fetch and duration, would be capable of generating waves of 20 to 30 feet or more. Visibility very seriously affected from dense blowing foam and spray. Freezing temperatures would create very hazardous freezing spray conditions. Small craft should stay in port. Conditions typical for a "Storm Warning".

 

High

"A High Threat to Life and Property Aboard Marine Vessels, Especially Small Craft, from Marine Winds/Seas."

Gale-force prevailing winds with very large combined seas. Sustained winds of 34 - 47 knots (Beaufort Scale 8 - 9). Winds of this strength, combined with a long fetch and duration, would be capable of generating waves of 10 to 20 feet. Visibility becoming affected by blowing foam and spray. Freezing temperatures could create hazardous freezing spray conditions. Small craft encouraged to seek safe harbor or stay in port. Conditions typical for a "Gale Warning".

 

Moderate

"A Moderate Threat to Life and Property Aboard Marine Vessels, Especially Small Craft, from Marine Winds/Seas."

Strong prevailing winds and large combined seas. Sustained winds of 22 - 33 knots (Beaufort Scale 6 - 7). Winds of this strength, combined with a long fetch and duration, would be capable of generating waves of 5 to 15 feet. Conditions typical for a "Small Craft Advisory".

 

Low

"A Low Threat to Life and Property Aboard Marine Vessels, Especially Small Craft, from Marine Winds/Seas."

Prevailing winds and combined seas are moderate. Sustained winds of 17 - 21 knots (Beaufort Scale 5). Winds of this strength, combined with a long fetch and duration, would be capable of generating waves of 3 to 6 feet. Conditions typical for a "Small Craft Advisory".

 

Very Low " A Very Low Threat to Life and Property Aboard Marine Vessels, Especially Small Craft, from Marine Winds/Seas."

Prevailing winds and combined seas becoming moderate. Sustained winds around 14 - 16 knots (Beaufort Scale 4). Winds of this strength, combined with a long fetch and duration, would be capable of generating waves of capable of driving seas of 3 to 4 feet. Conditions typical for "Small Craft To Exercise Caution".

 

Non-Threatening " No Discernable Threat to Life and Property Aboard Marine Vessels, Especially Small Craft, from Marine Winds/Seas."

Prevailing winds and combined seas are non-threatening.

[silveradosheriff]

Holy cow - 33 knots is considered moderate!

I'm not up for the 15 foot waves......

[jwl]

Holy cow - 33 knots is considered moderate!

I'm not up for the 15 foot waves......

 

I'm with ya man, I have had the boat out in some decent swells...rolling swells, not cresting ones on Lake Erie..I'm comfortable on the water..but no way my boat is seeing 15 footer unless some weird freak storm happened. ,if I am fishing the big water, I ALWAYS check a marine forcast, and some days we simply get to the launch and decide we aren't putting the boat in and go fishing somewhere else.

 

Pretty good insite into how they grade conditions

[Burtess]

"Small craft" is mentioned throughout the description, what is the definition of a "small craft"?

 

Burt