According to SMHI, flooding may occur in connection with the Storån north of Västervik and there is a risk of the nearby railway being flooded in the area.
The flows are expected to peak at the end of the week, but the forecast is very uncertain.
The warning applies until further notice.
Yellow warnings throughout Småland
In Småland, several yellow warnings are issued for high flows.
In several rivers, there is a risk of high water flows which, according to SMHI, occur on average every five to 25 years.
The rescue service in Kalmar has previously warned of high water flows in, among other places, Ljungbyå.
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Kalmar municipality is now warning that high flows in, among other things, the Ljungbyån.
See the dramatic pictures from Kalmar - click on "Show all".
Photo: Helmuth Petersson
- It has to do with the fact that there has been a lot of rain recently, while the mild air for the time of year has caused the snow to melt away quite quickly.
It has caused these high flows in small watercourses, says Christopher Greenland, meteorologist at SMHI, to TT.
It is the first time since the new system was introduced in 2021 that a red flood warning has been issued.
Photo: Johan Hallnäs/TT
In Kalmar and Kronoberg, the rivers Lagan, Nedre Mörrumsån, Ljungbyå and Lyckebyån are expected to be worst affected.
Please stay at home
The County Administrative Board in Jönköping County urges property owners in the affected areas to stay at home if possible, in order to keep an eye on their properties.
In Värnamo, the municipality has built barriers to prevent properties from being affected by penetrating water.
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SVT's reporter Johannes Tolf on site in central Värnamo where the water in Lagan is rising.
Photo: SVT
All yellow warnings for high water flows apply until further notice.
More rain expected
During the weekend and for a while, even more rain is expected to come in over Götaland.
- The center of gravity is over the southwestern parts, then it moves east and will touch Småland and maybe some parts of Östergötland as well, says Christopher Greenland, meteorologist at SMHI, to TT.