A Kauai Blog

Monday’s storm was really intense, but as the previous week, the normal weather came back fairly quickly. By Tuesday, there was hardly any rain on the coast, Wednesday and Thursday being almost sunny. It did rain more inland, and this created more run-off, but nothing like Monday’s fury.

First, some YouTube videos that are finally getting uploaded after the storm, starting with Opaeka’a falls and some other very temporary waterfalls:

You know, I did go looking for the waterfalls I had once seen on Nounou, but there were always too many clouds in the way.

Then there are the kids that found a wet hill to surf on. East-side residents can probably guess where this is:

And finally, what it was like to drive in the rain. I’ve seen more than one video where the driver is filming, but we’ll assume they were driving slowly to begin with.

That last one is rather telling, because the main damage from the storm was the closure of the Kapa’a Bypass due to a large culvert being eroded and undermining the roadway (photo at The Garden Island)–I wonder how many people drove over it in that condition. The state is working quickly to repair the culvert (HDOT has a release with photos) and reopen the road by next week.

In the meantime, the closure is causing bad traffic on the main road, because inland Kapa’a traffic to the Kawaihau and Kapahi neighborhoods (half the Kapa’a population) is stuck on the main road. Count on at least an extra 20-30 minutes to get through Kapa’a, both northbound and southbound at rush hour. At least in Hawaii, you get rainbows with your traffic jams:

There is another road closure on the main highway in Kilauea, again caused by a culvert eroding. That one took out half of the roadway, but they have a small detour in place and less traffic.

I did get out for the farmer’s market, and took Kamalu road behind the Sleeping Giant to avoid the traffic. I could tell I wasn’t the only person on the back roads. Do watch out for muddy spots where water washed some dirt over the road.

Another effect of the storm were all the pot holes in the roads from the extensive runoff. Once the water gets in a crack in the pavement, it washes away the dirt and digs a hole underneath.

Since I was out and about, I got some photos of the storm aftermath. Water was still flooding the side-streets down by the Coconut marketplace on Wednesday, but by today, there were only little lakes in the low-lying grass:

On the road to Lihue, the low lying areas around the county jail were flooded, including their vegetable gardens and outside exercise yard. You can see the drainage ditch in the forground overflowing.

On Kuamo’o Road, I stopped to see Opaeka’a falls again. The flow was somewhat diminshed, and the water no longer so brown, but the things to notice in this picture are the trees in between the two flows that were washed over and hanging on by their roots.

Driving up Olohena Road, we were treated to this nice waterfall. Most of the water from this little stream is diverted into an irrigation ditch, so it’s usually just a trickle. And this area wasn’t even visible until they cleared out all the hau bush a few years ago.

And here’s the irrigation ditch diversion just upstream. Like all the little streams in the area, the vegetation got scoured and the mud banks were eroded one or two feet higher than the normal flow.

I went all the way up to the arboratum, but of course the truck in the water had already been removed. Flow was still high, almost as deep as a tire, which is still probably enough to push a car off the crossing. Heed the signs, people:

Another consequence of the flood seems to be the stream gauge further inland on the other branch of the Wailua river. It stopped recording even before Monday’s huge peak, and the graph shows a malfunction indicator. I guess we’ll never really know the actual height of the water, unless somebody goes to read it off the markings on the trees.

Source: USGS stream gauge data

On my way back down, it was getting dark, but I noticed that the Coco Palms lagoons were overflowing and flooding the entire grounds. They do have a sluice gate to let out more water, but I suppose that would then flood the other buildings by the river, ones that are actually being used (thrift store, kayak rentals, and canoe club). Better to let the unoccupied buildings be flooded.

I think you can see the canoe docks under water at the top of this image.

Finally, I wanted to check on the rock pools at Lydgate. They were not as full of large debris as I imagined, because it looks like the storm swell overflowed the pools on the south side by the beach and carried away some of the branches.

However, both large and small pools were full of dark silt and the beaches partly covered in black mulch.

Another effect of the storm was that the beach itself was eroded from the runoff. I think some of the sand at the Lydgate pools is man-made, or at least replenished by truck, and a lot of it washed down into the water, leaving gullies in the underlying dirt.

Overall, the damage in the aftermath of the storm was minor. Some roads are being repaired, some people in Hanalei have real flood damage, and I do have some leaks in my roof to deal with. But for the size of the storm and amount of water that flowed, it seems like it could’ve been much worse. I expected to hear people talking about how they made it through, but instead most of the people I overheard were talking about the next storm already, due on Friday. We shall see.

The sound of the pouring rain woke me up this morning. It was barely light, but instead of lulling me back to sleep, the rain had me worried. This was the kind of rain that overflowed the gutters, saturated the ground, flowed around the house, and sometimes into the garage. I tried to go back to sleep, thinking the house was fine, it weathers these storms 2 or 3 times each year, but then I saw it was almost 8 am—the rainclouds were so thick they blotted out the light.

So I got out of bed, got out the umbrella and checked around the house. Sure enough, the gutters were overflowing, the back yard was saturated and covered deep puddles, and the garage was wet. There was also a mini waterfall down the neighbor’s hillside stairs. But other than some potted plants getting too much water and some erosion in the bare dirt of the garden, everything was fine.

It was also cold, so I put on socks and sweater and settled into a warm oatmeal breakfast with hot tea. The rain came and went, and came again. The heavy rain turned into a thunderstorm, with lightning and thunder off and on. The closest was a 3-one-thousand (3000 feet or 1km). The poor birds outside looked miserable:

Zebra Dove Java Sparrow

I checked the NOAA website with rain gauge information, thinking it would be worse on Wai’ale’ale:

Source: NOAA/National Weather Service

But no, the east side where I live was the rainiest, with Anahola getting over 5 inches (125mm) in just 3 hours. We couldn’t be too far behind, maybe 3.5-4 inches (88-100mm). Then I thought to check the stream gauge data for the Wailua river. This is tonight’s graph, with today’s peak data oddly missing (gauge overflow?). But what I saw in the morning was the continuous rise that could easily dwarf Friday’s peak.

Source: USGS realtime stream gauge data

So I talked the family into going to see the east-side waterfalls, so we went for a Sunday drive in the country. And we were not disappointed. First was Opaeka’a falls:

Across the road, the Wailua river was running brown and looking like it was going to overflow its banks. The Kamokila village down there was closed (but maybe it’s not open on Sunday):

Then we drove to Wailua falls. Everthing along the road was soaked, and the ditches by the golf course were full. But there didn’t seem to be any flooding, so the county’s work on clearing the vegetation out of the drainage ditches has paid off. Even the Kaua’i roosters were soaked, their feathers dull and their tails drooping.

Wailua falls was even more impressive, with the full flow of the South Fork plunging over. I estimate there was 2-3 feet of water going over the full width of the waterfall—except the one place on the left where a tree was still clinging to the edge:

We stood there for over 15 minutes with our umbrellas, fascinated at the wall of water tumbling down. The brown water flowed over in a solid sheet, then it separated into streams and finally separated into white water drops in very intricate and ever-changing patterns. I tried to get a photo of the effect, but my camera is not good enough, so this is just an enlargement of the previous photo:

Almost as impressive was the massive cloud of spray that was blowing the trees like a strong wind. We did see two tropic birds flying around, wondering why they were flying in the mist and what the view was like from there. And with all that water, the round pool at the bottom was gone, all the rocks and vegetation covered by the outflow.

On the way home, I pulled over at Wailua beach and walked on the bike path back across the new bridge. The river mouth was spread out wider than the length of the bridge:

The rains finally stopped in the afternoon, and there were even some nice sunset colors. Tonight, I looked up the total rain for the past 24 hours. Different parts of the island received rain at different times last night and today, but the overall totals are all above 3 inches (75 mm), with an average of 5.6 inches (142mm) across the entire island.

Source: NOAA/National Weather Service

More news the following day:

• The Hanalei river gauge had a similar graph, and the Hanalei bridge was closed. Reports are that water was flowing over the bridge. The difference was that in Hanalei, you could also see the waterfalls coming down the mountains.
• While the rainfall was impressive, this was pretty much a normal winter storm. Kaua’i usually gets 3 or 4 of these per year between November and March. The Garden Island newspaper has a similar photo of Opaeka’a falls with even more water from December 2010.
• Some storms have been much worse, for example when the Hanalei river valley flooded in November 2009 or the Kaloko dam broke in March 2006 after 30 days of rain.
• There was indeed a beautiful sunset after all the rain, if you were on the south or west side.
• Today was mostly sunny with only one rain-shower so far.