Four generations of measurers
These hydrological measurers are ordinary Finns who take measurements in their free time and voluntarily. Thanks to them, we know more about how water moves in water bodies and how snow and ice behave.
Many of these measurers have been making observations for decades. There are also those who have inherited the work from their father or mother and pass it on to their children, perhaps even their grandchildren. Kaisa Karjalahti, who lives in Pihtipudas, is one of them.
Walking on lake ice in any weather
Kaisa remembers how her mother, before the war, went to measure the ice at Lake Muurasjärvi in Pihtipudas. “My mother had an ice chisel that she used to make holes in the ice – ice drills weren't used at the time.” It was hard work, and sometimes her husband helped her. There were certain days on which the measurements had to be made, no matter the weather.
Kaisa thinks that her mother started measuring ice as early as 1910 or thereabouts. By the time of the war she had, in any case, been doing her measurement work for a long time. This is evidenced by a medal given to her during the interim peace by the President of the Republic for her diligent work.
When her mother's strength began to diminish, Kaisa and her family took up the measurement work. They visited the measuring point throughout the winter and drilled holes in the ice according to the instructions received from the authorities. They then measured the total thickness of the ice and the thickness of the different layers, the water level in the drilled hole and the thickness of the snow cover on the ice. “It wasn’t very quick work, as the measuring point is quite a distance from the beach,”
Kaisa says. Kaisa says that the measuring point is still in her name, even though she has already turned 90. “Now my daughter and grandsons are continuing the work on the ice.”
In addition to ice measurements, Kaisa and her mother have measured the water levels in Muurasjärvi. The water level used to be checked every morning, either from a scale on the beach or from a pole in the bottom of the lake. In 2008, an automatic meter was installed. At that time, Kaisa's measurements became less frequent, but they were still used to monitor the operation of the measuring device.
At the end of February 2018, Kaisa stopped making measurements completely entirely as the contracts of private observers were transferred from the Finnish Environment Institute to the South Ostrobothnia ELY Centre. Water level measurements were outsourced to companies.
Measurements provide valuable information
The work of Kaisa Karjalahti and other measurers is part of basic hydrological research. The data is used to study, for example, how and why the ice situation varies by region and over time. This helps to assess the impact of climate change.
Measurements are made to the nearest centimetre with the aid of an ice meter and so-called ice crust rods. Care must be taken to ensure that the different layers of ice are measured correctly. The average of three holes is calculated.
Muurasjärvi in Pihtipudas has one of the 46 ice thickness measurement points in Finland. The observations from Muurasjärvi start in 1910 – just as Kaisa thought. The series of observations is the longest in Finland.
Rewarding and interesting work
Kaisa's childhood home still stands on the shore of Lake Muurasjärvi, Kaisa continued to live in the area after she got married. It was not a long way to the ice, and in mid-winter the ice carried well. In spring, the ice got trickier. “There was always a watery zone in the same place, and you had to be careful,” Kaisa says.
One time, Kaisa's husband fell in on a measuring trip and nearly drowned. “He had a friend on the beach, but he was sitting on a hill and didn't hear the cries for help. The husband couldn’t get back on the ice in his wet winter clothes and had to swim through the slush until he finally caught a branch hanging over the ice. The branch provided enough support that he was able to pull himself onto the ice.”
No other incidents have occurred to Kaisa's family during her long career. And the job never felt dull or useless. “On the contrary, it has been interesting,” Kaisa says. Over the years, her cabinets have been filled with measurement data, from which you can see the ice conditions and water levels of past years. “We send the measurement results on paper by letter. This leaves a copy for us and memories of past decades for future generations.”
What do Kaisa’s archives tell us? Has the ice situation at Muurasjärvi changed? Kaisa answers the question cautiously and thoughtfully. “The ice seems to have become thinner, but the situation varies a lot from year to year.”
The Muurasjärvi time series data stored in the hydrological register agrees with her assessment.