4 Dec 2007

On the edge.

7 comments:

Mika said...

Here is an example of the fact, how ice is a very complex entity; changing in so many ways according to the weather and soil / water area type.

In southern Finland we have perhaps one of the best climates to have the most varied types of ice conditions; during all winter freezing and melting back and forth with and without of snow.

chrome3d said...

Yes, it freezes back and forth, which is sometimes frustrating. Don´t go walking on ice yet!

Dyaus said...

How thick the ice over water becomes? I think winter games must be popular in Finland.

Winter here is also good but at my location (Central India), it is not good. The weather becomes chilly (if you call 7 degree celcius a chilly atmo) around Christmas.

BTW pic is good. :)

PS - Have changed look of my blog. See it and please tell me how does it look. :)

Yrsa said...

I am no expert, but I have a vague memory of that cold winters we can get about 20cm:s of ice in southern Finland (or was this the requirement for driving a car on ice?). Maybe Mika can tell us more?
Anyway, this means we need to get a few cold weeks with temperatures of -10 to-20 degrees celsius.

Mika said...

Well, the thickness of ice varies greatly from winter to winter. Small water areas (lakes and ponds) will have the thickest ice layers. The sea will freez the least and the ice cover is allways very different on different parts of the water's surface especially on the sea; the thickest ice forms by the coast line (the most in the east) and during normal winters small western parts of open sea in the middle are usually free of ice all winter (freezing proceeds allways from the coast towards middle water areas). The sea means here The Gulf Of Finland.

During recent years we have had very mild winters a lot, like the last one. Then the formation of ice delayed even into mid January in southern Finland and for example the sea ice was at the thickest only about 30 cm at the end of February, allthough February was very cold in fact. In the mildest winters ice is found mainly just by the coast of the sea.

Normally the lake ice can be about 50 cm thick and the sea ice from 30 cm to 50 cm by the coast. In the 80's we had two extremely cold winters and then the ice in the small lakes got even thicker than 1 meter and 50 - 100 cm by the coastal areas of the sea as well. Then the whole sea area got thick ice and there was clearly a possibility to drive by car in Estonia from Finland over the sea. But the sea ice is often uneven and there are cracks and ice can also pile into "walls". Ice is in fact a rather elastic matter (especially when covering large areas) as well and it is therefore "living" all the time.

Usually the time of the thickest ice is happening during early March in southern Finland. The last spring was very exceptional due to the record warmth; all ice was gone at early April about 3 - 4 weeks earlier than normally.

So, these apply in southern Finland, but in Lapland it's completely a different story. There the lake ice melts away only during June on average years. But also there warm weather conditions have been prevailing during recent years and at this day as well the ice is much thinner than usually. In southern Finland it seems, that all little bit of ice will melt away this week from large areas and the ice formation will have to start from the beginning...

Yrsa said...

Thankyou Mika for your thorough comment (as always)!

Dyaus Spes said...

Thanks Mika :)