The Cumulative Cold Index

Courtesy of WOWSA, Huntington Beach, California.

Ger Kennedy, one of the most prolific ice swimmers in the world and the only male to complete the Ice Sevens, achieved another cold water swimming milestone: swimming 10 km in water under 10°C (50°F) in a solo point-to-point 10 km marathon swim from Sandycove Harbour to Bray Harbour.

The sub-10°C 10 km challenge brings to mind the Cumulative Cold Index, an extremely tough cold water swimming scale that may be outside the bounds of what is humanly possible. Steven Munatones says, “I say that now, but then again, the ice swimming and marathon swimming community always accepts all kinds of mind-blowing challenges – and then learns how to meet the challenge and exceed them over time.”

Cumulative Cold Index

• sub-10°C water for a 10 km swim
• sub-9°C water for a 9 km swim
• sub-8°C water for a 8 km swim
• sub-7°C water for a 7 km swim
• sub-6°C water for a 6 km swim
• sub-5°C water for a 5 km swim
• sub-4°C water for a 4 km swim
• sub-3°C water for a 3 km swim
• sub-2°C water for a 2 km swim
• sub-1°C water for a 1 km swim

Munatones recalled, “In addition to Kennedy’s sub-10°C 10 km swim, there have been others who have managed a 10 km distance within a longer marathon swim or channel crossing. There have been others who have completed sub-1°C 1 km swims, named the Zero Ice Milers:

• Cath Pendleton (UK) on 4 March 2020 in Hanusse Bay, Antarctica in 0.03°C water and -3.2°C air in 32:54
• Ger Kennedy (Ireland) on 24 February 2020 in Paradise Bay, Antarctica in 0.53°C water and -1.10°C air in 34:02
• Paul Eugen Dorin Georgescu (Romania) on 22 February 2020 in Hanusse Bay, Antarctica in 0.0°C water and 2.0°C air in 22:44
• Jaimie Monahan (USA) on 6 March 2018 in Paradise Harbour, Antarctica in 0.57°C water and 1.0°C air in 30:49 (1.01 miles)
• Ryan Stramrood (South Africa) on 2 March 2014 in Neko Harbour, Antarctica in -1.0°C water and 0.0°C air in 32:08
• Toks Viviers (South Africa) on 2 March 2014 in Paradise Bay, Antarctica in 0.5°C water and 0.0°C air in 25:30
• Gavin Pike (South Africa)on 2 March 2014 in Paradise Bay, Antarctica in 0.5°C water and 0.0°C air in 25:57
• Jaimie Monahan on 18 December 2018 in Tyumen, Russia in -0.03°C water and -31.0°C air in 30:20 (1.03 miles)
• Kate Steels on 24 December 2017 in South Lake, Shuangyashan City, China in 0.9°C water and -22.1°C air in 35:05 (1.01 miles)
• Ger Kennedy on 9 December 2017 in Tyumen, Russia in 0.5°C water and -18.8°C air in 43:10 (1.25 miles)
• Ger Kennedy on 16 January 2016 in Wild Water Armagh Pool, Ireland in 0.77°C water and 4.0°C air in 32:30
• Henri Kaarma on 15 December 2013 in Tyumen, Russia in 0.0°C water and 0.0°C air in 41:47 (1.49 miles)
• Ram Barkai on 23 March 2013 in Murmansk, Russia in 0.0°C water and 0.0°C air in 32:43
• Kieron Palframan on 23 March 2013 in Murmansk, Russia in 0.0°C water and 0.0°C air in 31:00
• Ryan Stramrood on 23 March 2013 in Murmansk, Russia in 0.0°C water and 0.0°C air in 30:00
• Henri Kaarma on 23 March 2013 in Murmansk, Russia in 0.0°C water and 0.0°C air in 33:00 (1.34 miles)
• Henri Kaarma on 16 December 2012 in Tyumen, Russia in 0.3°C water and -33.0°C air in 25:25 (1.37 miles)
• Aleksandr Brylin on 16 December 2012 in Tyumen, Russia in 0.3°C water and -33.0°C air in 1:05:06 (1.37 miles)
• Andrey Sychyovv on 16 December 2012 in Tyumen, Russia in 0.3°C water and -33.0°C air in 1:06:30 (1.37 miles)

“But I wonder where the bounds of impossibility lie?” pondered Munatones. “At some point, the distance and the cold get too much. At least I would think. These Cumulative Cold Index swims seem particularly tough:

• sub-6°C water for a 6 km swim
• sub-5°C water for a 5 km swim
• sub-4°C water for a 4 km swim
• sub-3°C water for a 3 km swim
• sub-2°C water for a 2 km swim

But swimmers like Henri Kaarma (2.39 km in 0.0°C water), and Kaarma, Aleksandr Brylin, and Andrey Sychyovv have already swum 2.2 km in 0.3°C water. So who knows where the true potential lies for ice swimmers?”

Ram Barkai, founder of the International Ice Swimming Association, believes the hardest distance would be a 5 km swim in sub-5°C water.

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