Among the North Frisian Islands off Germany's North Sea coast is a string of tiny low-lying elevations known as Halligen, or the Hallig islands. They have zero to very few coastal defenses, so whenever a storm tide builds in the waters around them, the sea easily rises high enough to swallow everything on the islands but the man-made dwelling mounds or Warften upon which people live.

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Residents of Hallig Hooge explain what happens when the sea comes calling in a phenomenon known as Land unter — quite literally land under. Because their Hallig has a low dike, their land is largely spared inundation in the summer months. In the winter, they have an average of four or five flooding events each year. Other Halligen that don't have a dike, can have up to 50 annually.

Karen Tiemann was born and bred on Hooge, and came back in her late twenties after spending several years on the mainland. She's glad to have lived elsewhere, but also to have ultimately returned. She says life on the Hallig makes her realize just how small people really are. She runs a holiday home and a cafe in a building dating back to 1750.

"For me, a Land unter is just a normal part of life. What is exhausting, is when the Land unter comes too early when there are too many animals out in the fields that have to be fetched up onto the dwelling mounds, and when the whole holiday season is still in full swing, which means the toilet truck, the summer furniture, the garbage cans are still out. You have to bring everything in, otherwise it gets lost. And when it gets so bad that the water almost gets into the dwelling mounds, or does get inside them. That's annoying.

I witnessed the flood of 1976 and the cellar in the house opposite was full and here in our house it was 10 centimeters (3.9 inches) high. Since I was still a child and because everyone around me was calm, I didn't panic. Except for a brief moment when I went down to the cellar to check how high the water was and could no longer close the door. But I finally managed to get it shut."

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Jan Dell Missier's family has lived on Hooge for generations. He helps maintain the low coastal defenses that prevent the Hallig from being inundated too often during the summer months when cows and sheep are grazing on the fields between the dwelling mounds. He also keeps cattle of his own and describes what happens with the animals during a summer inundation.

"If it happens in the season when the animals, the cows, are here, you have to make sure you get them all up onto the dwelling mound on time. People help each other. 

Everybody makes sure that whatever they have on the road or down at ground level is brought up to the dwelling mound. But since we're informed on time, we always manage that pretty well. 

But when we get a storm surge warning and they say it's going to be either a meter or a meter and a half [above normal sea level], then you wait a long time to see whether it's really coming or not. And if it then does come, it can get a bit hectic.

Then this [area in front of the houses on the dwelling mound] up here is full of animals. They don't come by themselves, you have to chase them up and then they stay here until the water is gone."

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Sandra Wendt was also born on Hooge. Like many residents, she has a holiday home, but she also works at the local cinema which shows only one film about a flooding event. She has witnessed the sea climb over the low dike on the island countless times, and barring the ferocious storms of late 2013, says she enjoys the opportunity to batten down the hatches and watch nature run its course. 

"It's a really great experience. You know it's coming, you know the water is going to flood the Hallig, and you know it'll drain out again. It doesn't do much harm. It's something a lot of people would really like to witness, because it's a chance to watch nature move at its own pace. And that is something incredibly beautiful. It's part of life here.

We know when we have to be at home, not least, because sometimes the roads in front of the dwelling mound are the first things to be flooded. You do your shopping and then you go home and you're there while nature gets to work. You have time to do things like bake biscuits or finally catch up with the neighbors for a chat. 

It's always so nice for us to witness. And you really do sit and watch nature. It's a period of calm during the winter, when we have a bit of time for our land and we can follow our own rhythm."