Isdrift på Vättern

[thureb]

har jag stor respekt för. Alla Vätternskridskoåkare bör beakta råden på http://www.llk.se/register/vattern.htm

Idag räddades 6 skridskoåkare vid Visingsö med hjälp av helikopter:
http://www.dn.se/nyheter/sverige/fast-pa-drivande-isflak-i-vattern
http://gt.expressen.se/nyheter/1.2344520/hollandare-fast-pa-isflak-i-vattern

Thure

 

[Sarvi]

Bra att det slutade väl. Finns en färsk färdrapport på skridskonätet om en LLK-tur som också stötte på en från början beskedlig råk som snabbt vidgades och blev oöverstiglig, men där gruppen tog sig över där råken gick in mot land.

En sak som jag reflekterar över är att det känns som det blev mer blåst idag än vad SMHI prognosticerade häromdagen. När jag kollade prognosen för fredag tidigare för någon dag sedan vill jag minnas att det förutspåddes 5-6 m/s, kollar man på mätstationen på Stora Hammarsundsbron (som i och för sig sitter väldigt exponerat och högt) har medelvinden varit 8-12 m/s och maxvinden 12-16 m/s under dagen.

 

[ulfhe]

På tv

Smålandsnytt

 

[ulfhe]

Vindprognos

Man kan undra vad det är för vind som SMHI och YR anger. Är det markvind över land eller är det höjdvinden? Friktionen över isen är så låg att vinden över isen säkert inte skiljer sig särskilt mycket från höjdvinden.

Ulf

 

[RobM]

Report about Visingsö incident 2011-02-25

Idag räddades 6 skridskoåkare vid Visingsö med hjälp av helikopter:
http://www.dn.se/nyheter/sverige/fast-pa-drivande-isflak-i-vattern
http://gt.expressen.se/nyheter/1.2344520/hollandare-fast-pa-isflak-i-vattern

Thure

A detailed report in English with facts and lessons-learned about this incident is now available at:
http://www.hlsk.nl/documents/111231_VisingsoIncident2011_v10.pdf

The report links to a Google Picasaweb album with pictures and movies, that can also be viewed seperately at:
https://picasaweb.google.com/lh/sre...017242175&target=ALBUM&id=5647855830912086289

As mentioned in the report: remarks, suggestions, different opinions: all welcome at my emailaddress that can be found in the report. Remarks here at Utsidan are also welcome: a kind request to post them in English, so that the people involved, leaders at HLSK, and so on, can read and understand what is being said.

At the ice-conference in Finland 21 january 2012, there is room to have a discussion about the incident and lessons learned, if there is any interest.

Mvh, Rob Mulders.

 

[JoostD]

Suggestion to report VisingsoIncident2011

Suggestion to the report:

Not only every multi-day-trip, but also a daytrip needs a leader and sub-leader? The sub-leader should be able to bring back the group to the departure-place in case the leader becomes unable to do. If not sure, the group should not depart on the lake at all. During the trip this should limit the track chosen.

As a lesson learned:
In case of a potential downwind-situation on a big lake, the group should not be more than 5 metres from the bank of the lake? Otherwise is is not possible to escape to the bank if the ice starts drifting downwind.

Just before stepping on the ice at the start of the trip and after fika, at all times there should be a moment of investigation the weather, with a moment of decisionmaking to depart or not and in wich direction. This is regardless any internetinvestigation in advance.

A detailed report in English with facts and lessons-learned about this incident is now available at:
http://www.hlsk.nl/documents/111231_VisingsoIncident2011_v10.pdf

The report links to a Google Picasaweb album with pictures and movies, that can also be viewed seperately at:
https://picasaweb.google.com/lh/sre...017242175&target=ALBUM&id=5647855830912086289

As mentioned in the report: remarks, suggestions, different opinions: all welcome at my emailaddress that can be found in the report. Remarks here at Utsidan are also welcome: a kind request to post them in English, so that the people involved, leaders at HLSK, and so on, can read and understand what is being said.

At the ice-conference in Finland 21 january 2012, there is room to have a discussion about the incident and lessons learned, if there is any interest.

Mvh, Rob Mulders.

 

[thureb]

Excellent report

There was quite a long chain of events and circumstances before and during the 25:th of February which are important in order to draw proper conclusions for trying to avoid future similar incidents or accidents.

My understanding is that the group and probably the whole HLSK had to little understanding about the ice drift problems on lake Vättern in winds above 6 m/s and especially that the north point of Visingsö is a trouble spot in south and southwest winds.

There were other problems in other skating groups on Lake Vättern the same day as is mentioned in reports on skridskonätet.

Local expertise is important when you skate or ski in changing and potentially dangerous winter conditions.

I would recommend everybody who skate and large lakes as Vättern or Vänern to try to team up with skaters who have experience from such areas.

Vattern’s large surfaces freeze quite seldom and large experience from several tours on
lake Vättern is however not common among even quite experienced Swedish skaters.

I have more respect for Lake Vättern than for all other lakes and seas in Sweden, Finland, Norway, Denmark, Germany and the Netherlands I have skated on during the last 5 decades.
I have experienced ice drift at the north part of Visingsö on two occasions 1986 and 1987 in winds around 5 m/s.

Thure