Entries by robertdill (15)

Monday
May262014

Alcohol and Mortality

Booze plays an outsized role in snowmobile deaths on ice.  

 

  • In Wisconsin over eight years 72% of the 178 riders who died were impaired.  For accidents on ice the rate was even higher: 87% of 46 riders.  
  • 76% of sled+ice fatalities occur at night.  The combination of impairment and darkness creates an especially dangerous situation. 
  • It seems that impaired riders  choose to ride on lakes and rivers at night to reduce their arrest risk. 

 

Click here for a review of the Wisconsin data and a look at the dramatic increase in risk associated with higher impairment levels. 

Bob

Tuesday
Apr152014

Ice Out

10"  piece of very rotten S2 ice surrounded by individual crystals that have separated from the intact ice.

 

Lake Champlain has lost most of its ice in the past week, some of it in windy conditions and some of it with relatively little wind.  Yesterday (April 14) about 35 square miles of the Inland Sea ice went out in a few hours in south winds around 30 mph and temps in the 70's.


Inland Sea on Lake Champlain (google maps)

The ice was being blown toward the north at about 1 mph.  I would have thought that this would have lead to significant ice shoves, however there were very few. There was some rafting but nowhere near enough to account for the amount of ice moving north.  It appears that even when ice covers most of the surface, there is enough stirring of the underlying water to get the deeper, warmer (34-36 degrees) up to the surface where it  melts the ice (along with the sun and warm wind). 

Ice pieces moring north (the peices are roughly 10' in dimension). The openings between the ice pieces would appear  quickly (15 minutes), appearently with a sift to a more off shore wind direction.  

One of very few relatively small ice shoves.  This one is at KillKare State Park in St Albans, VT.

Bob


Wednesday
Apr092014

Candled Ice

 

14" ,stage 6, rotten candled ice with a properly attired swimmer (dry suit, life jacket, warm clothes, ice claws, and a friend with a throw rope). 

Spring is a very popular time to get wet and it often occurs when people are trying for one more day on the ice.  While much of the ice belt has melted there is still ice in the northern Midwest, Canada as well some higher elevation lakes in northern New England. 

Thick, fine grained ice evolves into an especially weak form of ice usually called 'candled ice'.  NOTE: when this post was originally written two weeks ago I call this 'Mattress Ice'.  A closer reading of the Swedish definition of their word 'madrassis' refers to ice with  larger grain size that behaves very differently in a breakthrough. True Mattress ice is also rarely experienced as it only occurs on very rotten ice sheets.  

The crystals of candled ice are irregular rods that are vertical and are often as long as the ice sheet thickness.  The crystal boundaries have melted completely and they are held together largely by the fact that they are all stacked together. When weight is applied to the ice surface, it gives a little as the crystals shift a small amount (0.2"?).  Some times this will hold you (thaw stage 5), some times it won't (thaw stage 6).  

 The following are three stories of breakthroughs on rotten candled ice.

1) Three days ago a fishermen who was sure there was 16" of ice and he felt the need for one more day on the ice.   We were 10 days into spring thaw with 60 thaw degree days at that point (enough to melt several inches of thickness).  About a mile off shore  he stepped on some dark weak ice (candled ice).  He was lucky to only get one leg wet and not to fall through again on the way back in.   Rotten candled ice often results in one leg break throughs (maybe 30% of the time for for cautiously walking people).

 2) Yesterday, a couple hundred feet from shore on the same ice the fisherman was on,  I stepped through the a patch of rotten candled ice shown in the picture above.  By leaning to the side as I went in I avoided getting wet above my legs (and, of course, I had my dry suit, life jacket, neoprene gloves, and several people within shouting range).  As you can see from the picture, with the residual white crust, it is hard to see the grain size. This ice is way past being reasonable for recreational uses.

  My  8.5 foot test pole has great reach and is usually pretty effective at identifying weak ice but with thick, very weak ice the pole will blast through most everywhere with a hard jab.  The lighter Swedish test poles work a little better at indicating what ice is likely to hold you what ice will not.

3) Today I met a fisherman who was planning to fish from shore, having fallen in on rotten candled  ice a few years ago.  His swim was at Sandbar State Park.   He had walked about half  a mile out before falling in.  He got himself out, drove 20 miles back to home and never even put his bait in the water. He did not tell anyone for a couple years for fear of how stupid his friends would think he was. 

Rotten candled ice is especially tricky when it is cold enough to set up a little overnight ice.  That lets you get out  on the ice that feels feels strong before it gets weak as the sun rethaws the overnight ice.

Bob

Saturday
Apr052014

April 4-New Video on Skating Across Lake Champlain

 

Dave Hough (Keene NY) posted a great video of an over and back trip with five of his friends across Lake Champlain from the mouth of the Little Ausable River to the Colchester Causeway in late January.

The images in this post are all screen captures from Dave's video

Improvised Ice Sled

Bob

Monday
Mar172014

Staint Patrick's Day 

Lake Champlain makes beauriful green ice all season long, not just on Saint Patrick's Day!

Click here for an article on colors in lake ice.

Bob