My travel companion had wanted to see orangutans in the wild. The village of Bukit Lawang is 86 kilometres northwest of Medan in north Sumatra, and there you can hire a guide and tramp into the Gunung Leuser National Park and -- if you are lucky -- see orangutans swinging through the jungle canopy above mobs of tourists. Sadly the Leuser rainforest is still under attack from illegal logging and palm oil plantations.
On November 2, 2003, a flash flood came down the Bahorok River and, at Bukit Lawang, it swept away 400 houses, three mosques, eight bridges, 280 kiosks and food stalls, 35 hotels and guest houses and 239 people died (five of them tourists).
Illegal loggers had come over the ridge from a neighbouring catchment and harvested hardwoods in the Bahorok headwaters. A tropical downpour formed a temporary dam of logging slash, which then gave way. They say the wall of water and logs sounded like a freight train as it approached Bukit Lawang.
Eight months later, the Indonesians had rebuilt their infrastructure, were living on the riverbank again and open for business.
According to the geographer Kenneth Cumberland in Landmarks (1981), New Zealand's North Island experiences some of the most severe, localised three-day or four-day rainstorms in the world.
In February 1938, such a storm hit a region extending 50 to 60 kilometres around Gisborne. It was so extreme that small streams rose as much as 18 metres. A public works camp by the Kopuawhara River, near the Mahia peninsula, was overwhelmed by a wall of floodwater and 21 men were killed.
While our new house is being built, we are living in a caravan at our forestry block up the river. During the June 2015 flood, over a metre of water had swept through where our caravan is parked.
Last week, after a day of rain, my travel companion kept glancing nervously out the window.
"The river is flooding," she said as the water turned brown and started to rise.
"That's what rivers do when it rains," I replied.
"Horizons modelling says this flood could be the big one," she said as I prepared to go into town for band practice.
"I doubt it -- but don't worry, it will take a while to go over the road," I countered, realising that it would be unfair to leave her alone in the dark. "Besides, it is a half moon and the tides won't be too high."
"Horizons is saying it will be 19 metres at Pipiriki and it will be higher than 2015," she reported the next morning after I had shifted the caravan to higher ground at the other end of the paddock, above the 2015 high-water mark.
"That's the very extreme end of a range of possibilities," I said, trying to sound reassuring and preferring to stay and monitor the situation.
"Don't you care about me -- and what about Pipi?" she accused unfairly, running around in the pouring rain and loading stuff into the ute.
For the sake of marital harmony I moved the caravan to even higher ground down the road at the eco village, where the residents were muttering sagely about climate change.
"What about 1938?" I challenged.
�When Fred Frederikse is not building, he is a self-directed student of geography and traveller. In his spare time he is co-chairman of the Whanganui Musicians' Club.
