Mentawai historical swell data by month

As a Surfline premium member, I get access to crazy amounts of data.  Over the last year or so I have been manually collecting data for the Mentawai/Sumatra area day by day from Surfline's LOLA model.

To the best of my knowledge, this data for Sumatra isn't based on anything collected by scientific instruments in Indonesian waters or human observation.  It's just the output from a complex proprietary Surfline algorithm for predicting swell height, period, and direction based on limited, but real wind speed, direction, and sea state data collected by weather stations, buoys, and US government satellites.  As such, it needs to be taken with a grain of salt.

This narrow swell-focused view does not take into account wind or tides, but I feel these are reasonable to ignore.  With the smaller tidal range west of Sumatra most spots work acceptably on most tides and tide flow directions.  With respect to wind, Sumatra is noted for light and variable wind.  Strong, consistent winds from one direction do happen (like the S/SE pattern July-Sept 2006) but such patterns are relatively rare until you go south of the Mentawais on mainland Sumatra. 

So on to the numbers - what I have here is the average "Swell Energy" for each month from July 07-February 09.  I use quotes around swell energy because if Surfline said a given day was 3-4 ft at 15 seconds, I just add the smaller height number to the period to get Swell Energy.  So a pumping, big-as-it-gets swell of 9 ft 17 sec would be a 26 whereas some 3 ft 12 sec junk would be a 15.  This works because wave energy is a function of both swell height squared and swell period squared.  To some degree, the two are fairly interchangeable.  This isn't to say that 3 ft 17 sec will look just like 6 ft 14 seconds at your local break, but that level of complexity is spot-specific and beyond what I can possibly figure out.

July 2007 Average 21.1

August 2007 Average 21.6

September 2007 Average 20.3

October 2007 Average 18.4

November 2007 Average 16.9

December 2007 Average 15.1

January 2008 Average 16.1

February 2008 Average 16.8

March 2008 Average 17.9

April 2008 Average 18.9

May 2008 Average 19.9

June 2008 Average 19.8

July 2008 Average 20.6

August 2008 Average 19.9

September 2008 Average 19.7

October 2008 Average 17.2

November 2008 Average 13.6

December 2008 Average 15.2

January 2008 Average 16.5

February 2008 Average 14.9

I know there are a lot of sites out there that crunch historical data and give it away for free like this one - but there are differences.  Since magicseaweed has to cover all sorts of crappy unreliable spots in Florida, the Caribbean, Brazil, etc, their bar for "ridable" is a lot lower than the average Mentawai boat trip punter.  To say that Macaroni's is "rideable" between 62% and 90% in January might be true in the Florida sense, but if you pulled up there and the swell was 4 ft 11 sec, the guide wouldn't even drop the anchor before pulling a U-turn and heading for Thunder's.

From what I have seen swell energy of 19 or 20 should be enough juice to make swell magnets go overhead+ and get all but the neediest spots into the shoulder-to-head high range.  This is the swell that gives you the session of the trip, everyone's best wave of the trip, all the keeper photos and video clips, and sticks in your mind and makes you determined to come back next year.  In peak season, you can see the islands off Sumatra do that pretty consistently.

Has " Indies Explorer " left the Mentawai charter scene for good?

Indies Explorer boat first caught my eye when featured in a surf video a while back. It's one of the largest and most recognizable charter boats in Indonesia, a Pinissi schooner over 100 feet long, bright white with two tall sailing masts. I saw this iconic boat at Thunders in August 2006. It was a small day of forgettable surf and 40 people were in the water groveling for some chest-high sets. Indies Trader 4 was also there, so we felt pretty smart that our groveling session didn't cost $1200/person/day.

About Indies Explorer, when I was looking for a Mentawais charter boat I was intrigued by the large size and relatively low per-day cost, but the boat holds 12 guests which was sort of a turn-off and the schedule didn't work out for the dates I had available. That day at Thunders I felt fortunate to have skipped since it looked like the boat didn't have much shaded common space with a view of the surf (always a precious commodity on surf trips). The sleeping cabins below decks all had ventiliation hatches in the middle of the main deck and the deck sloped up forward and aft, basically killing the most logical place for a picnic table, hammocks, etc. When we drove by in our dinghy there were also bits around the stern that looked kind of beat up and run-down. I scrutinized the other boats we came across as much as possible - there are only so many boats over there and I wanted to see what kind of shape they were in, did they pitch and roll a lot when anchored, etc. The truth is that some boats just look better on the internet and Indies Explorer is probably one of them. Using 6-year-old photos on the booking web site is one slightly deceptive practice - recent boat photos are always a good thing to ask for.

Anyway to make a long story short, I was thinking about all this because I recently learned that an overnight storm washed "a big white wooden sailboat" up on the beach in Padang. I don't think there are many other such craft near Padang besides Indies Explorer. For all the things that looked impractical about it you can'd deny the boat has soul. If anyone is thinking about going on Indies Explorer in 2008 or knows if it did in fact hit the beach drop me a line.

Rags Right is gone - 3 ft. of reef uplift in Southern Mentawais

The article below came out on 9/28. I've been getting married, getting away, and getting sick so have been kind out out of it.

http://www.nytimes.com/2007/10/02/sports/othersports/02surf.html

This article quotes Scuzz (Chris Scurrah) and Christina of Sumatran Surfaris. Sumatran Surfaris is currently doing a company trip/relief mission combo and probably invited some media along to cover the trip. The article quotes respected CalTech scientist Kerry Sieh as saying that the southen Mentawais have been lifted roughly 3 feet according to GPS. The article notes that Rags Right is gone and Macca's is shorter, shallower, and more dangerous. As far as other spots go, if Rags Right is affected that much then Thunders is probably pretty different with lots of exposed reef on the inside. It was pretty shallow/hollow but rideable from 3-5 ft faces, hard to know how it will be affected. The Hole may also be gone since it was shallow/heavy to begin with and pretty far south. Green bush was named by Surfing Magazine, has been featured in videos, looks shallow, and I believe it's near macaroni's so it could be gone also.

Did the recent 8.4 Sumatra quake affect surf spots in the Mentawais?

First of all I don't have any information now, but will post any I receive as I hear back from friends or contacts with first or second hand experience. The only people who know the real scoop are out on boats now or will be going out over the next month or so.

I realize it is a bit crass to be discussing surf spot changes when there has been loss of life and much loss of property in the area, but if you can take a longer term view the world class spots offshore from Sumatra are some of the most consistent in the world and are one of the best chances to bringing low-impact, high-dollar tourism and development to this area. Ask yourself, would Dr. Dave Jenkins have started Surf Aid to prevent malaria in a group of rural, undeveloped islands on the _eastern_ side of Sumatra? Surf spot changes (which are bound to be mostly negative) will impact the long-term growth prospects of this region. I hope there were no negative effects on spots and that the word gets out that Macca's is still working while people are still thinking about where to go for next season.

Generally speaking it usually takes an 8+ earthquake to materially deform the earth's surface, and the 8.6 that hit North of Nias in March of 2005 has had a big effect on spots in Nias, the Hinakos, Simeulue, and the Banyaks. I did some imprecise Google Earth measurements and Lagundri Bay on Nias is about the same distance from the 8.6 Northern Sumatra quake as the southern end of South Pagai in the Mentawais is from the recent 8.4 quake. I realize the most recent quake may or may not have created much uplift but just on distance alone it still could affect Thunders, The Hole, and other secret spots in the southern Ments. Waves on Enggano or mainland Sumatra could be more significantly affected. Finally, Northern Sipora (the telescopes area) suffered a direct hit from a 7.2 aftershock. That's almost as big as the Loma Prieta earthquake that hit the Bay Area in 1989. Even if there was no effect on local surf spots it might be a bit harder to find a family to stay with if you want to go feral in Tua Pajet.