Hawaii tsunami warning 10:30 PM HST Saturday

[Nords]

The tsunami sirens just sounded for the earthquake off Western Canada. The tsunami is expected to arrive in Hawaii in about 90 minutes, around 10:30 PM HST. Initial forecast is a foot on Oahu's North Shore and five feet on Kahului, Maui. The waves have passed the last PACNORWEST sea buoy outbound and we won't have a forecast update at Hawaii buoys until after 10 PM.

We're at home in Central Oahu, elevation 450 feet, and don't expect any problems in our neighborhood. Waikiki visitors & residents are evacuating "vertically" to higher floors of the buildings. Ala Moana Shopping Center is evacuating, as are the rest of Oahu's coastal areas. Hopefully there's only minor damage on Oahu harbors & shores. Kahului and Hilo (on Hawaii Island), where there is more risk of damage, are evacuating to higher ground. Right now the greatest concern is panic and bad driving.

One North Shore road is already reported to be jammed in both directions-- one group of residents evacuating, another group driving up to Haleiwa to see the surge.

Local updates at KITV.com, HawaiiNewsNow.com, and Twitter hashtag #tsunami. I may not be back online until later Sunday.

[obgyn65]

Good luck and stay safe.

[powerplay]

Hope everyone stays safe.

[bssc]

Stay safe and all that good stuff.

[Nemo2]

Surf's up!

[donheff]

So what is the verdict? Did it cause any problems?

[audreyh1]

Sounds like Hawaii had almost no water surge - lucky!

That was the biggest British Columbia earthquake since 1940 something (7.7 scale). I bet my friends in Victoria felt the rocking.

[Nords]

All clear. Sunrise may reveal more damage, but so far everyone seems very lucky.

Quote:

Originally Posted by donheff So what is the verdict? Did it cause any problems?

There was a long lull after the outbound tsunami wave (moving at 500-600 MPH) left the Canadian & west-coast buoys. After the 2004 Indonesian tsunami, Hawaii added some more local buoys-- but those offer less than an hour of warning. So there was a period of 2-3 hours where everyone was speculating and tempted to engage in ill-advised behavior.

The quake was less than last year but tides were high last night (well, two feet isn't much by Mainland standards, but that's very big around here) and it happened in the dark. A Makapu'u Point buoy initially showed a drop of three feet followed by a rise of 1.6 feet. That caused some excitement. But then Kahului came in at 1-2 feet and Hilo harbors saw "only" four feet. The waves were surging every 5-10 minutes instead of 30+ minutes, which indicated that the tsunami had less energy and would probably not go higher. The first wave is frequently the smallest and the worst doesn't happen for another 2-3 waves. Even then the tsunami energy ricochets around the islands for as long as 24 hours before dissipating. The initial warning went out at 7:15 PM and the sirens lit off at 8 PM, so by 1 AM everyone was a tad burned out. But the Civil Defense people were reluctant to give the all-clear too soon.

Meanwhile the timing was the worst I've ever remembered since the history of the 1946 disaster. Visitor counts this year are setting new records. Saturday night, Hallowe'en party weekend, Waikiki & Ala Moana were packed. Partyers were in costume and much less than sober than usual. At least 5000 people were in shelters or camping out last night on all the islands. Airports were grounding the flights as quickly as possible and canceling the rest of the schedule. (Honolulu's reef runway is at an elevation of about six feet, even before the two-foot tide.) The Marines evacuated Kaneohe Base last night (1700+ servicemembers & families), and the rest of the Kailua/Kaneohe residents were right behind them. Everyone on the Ewa Plain headed straight upslope to Makakilo community centers and parks.

Quote:

Originally Posted by Nemo2 Surf's up!

Don't get me started.

Many Darwin Award nominees "distinguished" themselves last night, and there were a few deaths. There were the usual idiots rushing out to the ends of the piers and standing in the shorebreak with their cell phone cameras-- and they were probably even sober. I'm sure a lot of people had a bit too much to drink and decided to drive anyway ("Because it's an emergency!"), and I bet almost every driver was checking their cell phone for the latest danger updates. People raced to stores to buy the traditional tsunami supplies of rice, bottled water, batteries, and toilet paper. (Because, you know, nobody stores that stuff at home and we might not ever get any more of it after the tsunami.) Several tweets reported fistfights at gas stations. Boaters spent the night at sea, I doubt that all of them were ready for a sortie, and harbormasters didn't re-open the piers until after sunrise. I bet the Coast Guard is busy this morning.

Kaukonahua Road (to Waialua & Haleiwa) was jammed with vehicles leaving the North Shore. But I read that it was also jammed in the opposite direction with lookie-lookies driving up there for the show. Several serious vehicle accidents took at least one life last night.

Social media was awesome, broadcast media pretty much sucked. Twitter's #tsunami hashtag worked very well (it trended at #2) and locals were updating their Facebook status. Lots of on-scene reporting from beach webcams and mobile users, too. Local media was crowdsourced by the audience over 3G networks while their staff were stuck in traffic, stopped at roadblocks, or in the studio. I got faster/better updates from Twitter than from any other source, although there was 100x the volume and probably only 1% signal/noise ratio. I'd see a local tweet on the hashtag, and then a couple minutes later a KITV anchor would say "This just in from our on-scene reporter..."

No, I'm not going surfing today, but I'll be out there on Monday.

I hope everyone gets through Sandy at least as well as we got through this.

[Meadbh]

I flew into Vancouver about 30 minutes before the quake and nobody here noticed a thing. However, people in centres at more northerly latitudes (Prince Rupert, Prince George and into Alberta) definitely felt it. This quake was in the Offshore Region, which is different from the Cascadia Subduction Zone. I definitely don't want to be around when that one happens!

Seismic zones in Western Canada

[kumquat]

Interesting:

Quake hit at 8:04 local time. I'm guessing that's also Vancouver time. Vancouver is GMT -8. Honolulu is GMT -10 if google is correct.

That means the wave would get to Hawaii in 4.5 hours? Could be, seems fast. Am I making a simple arithmetic error or do waves move that fast?

[Nords]

Quote:

Originally Posted by kumquat Interesting: Quake hit at 8:04 local time. I'm guessing that's also Vancouver time. Vancouver is GMT -8. Honolulu is GMT -10 if google is correct. That means the wave would get to Hawaii in 4.5 hours? Could be, seems fast. Am I making a simple arithmetic error or do waves move that fast?

The short answer is "500-600 MPH".

The waves are very tiny in height (only measured in millimeters or maybe inches) but they're thousands of feet, even miles long. There are more details & diagrams here:
Tsunami Characteristics - PDC

Here's the sequence of messages issued by the Pacific Tsunami Warning Center:
http://ptwc.weather.gov/index.php
(This link is only good for the last 30 days of traffic.)

The quake hit at 0304Z (UTC) and set off everyone's seismographs. The PTWC spend a half-hour looking for buoy data and running computer "what if" models, but the quake location & magnitude didn't seem to indicate the formation of a tsunami.

That assessment changed at 0514Z (two hours after the quake) when two DART II buoys started bouncing around-- all of 2.5 inches. (Scroll down this link NDBC - Deep-ocean Assessment and Reporting of Tsunamis (DART®) Description for the system diagram of a DART buoy.) Added to the evidence of a tide gauge in British Columbia, they called a warning with an arrival of a bit more than three hours later.

This diagram shows the location of various Pacific sensors.
http://www.noaanews.noaa.gov/stories...ylocations.jpg
Notice the big gap between the Pacific rim buoys and the island buoys. For most of that three hours, there was no data to update the forecast. Satellites couldn't pick the tsunami wave out of the clutter and shipping wouldn't even notice it. The wave finally passed under a few weather buoys to the north of the islands-- not special-purpose tsunami buoys, but good enough.

My spouse is an oceanographer and she used to be a Navy Emergency Preparedness Liaison Officer working with FEMA and Hawaii Civil Defense, so she talked me through the events that happened after the 0514Z warning. The "problem" was that the quake wasn't big enough to pose an immediate threat, and the wave was still far enough away to allow for a little deliberate thought before action. The PTWC computer model was calling for shore waves of at least a couple of feet, but not necessarily threatening enough for the watch officer's procedures to call for immediately pushing the button to sound the tsunami sirens. Instead they had to discuss the issues (safety vs budget) with CD and make a courtesy call to the governor. (This is the process that they've worked out over the years, although now they might decide to lower the number to let the watch officer hit the button a little sooner.) So the first siren fired up around 0545Z, with just two hours and 45 minutes of warning.

I was sitting at the computer when the sirens went off, and Twitter had the answer faster than the local news media websites could load. (Luckily I chose to search for hashtag #tsunami rather than #hurricane or #nuclearattack, so I got the right answer on the first guess.) Spouse had to channel check her TiVo for a bit before she got to the CD crawler.

I guess the most pain was felt by the traffic police. I don't know if 165 minutes was not enough time for the traffic to clear the streets, or too much time to give all the lookie-lookies the idea to drive down to the beach to see the show. But by 0810Z (T-20) the police were ordering people to abandon their cars in the middle of the traffic jam and start walking smartly inland/uphill. At 0830Z the beach webcam showed a couple people actually wading into the shorebreak to record the arrival on their smartphones.

When a tsunami "arrives" it can be a six-hour event. It can literally take more than an hour for the bigger waves to hit, so it was 1100Z (another 2.5 hours after the tsunami's arrival, 1 AM Honolulu time) before PTWC was ready to cancel the warning. Even then CD waited another hour (until Hilo had settled down) before deciding to declare all clear.

People still died in the traffic jams, but hopefully lives were saved by sounding the alarm. It'll be interesting to read the after-action reports over the next few weeks and see what procedures change.

[kumquat]

Quote:

Originally Posted by Nords People still died in the traffic jams, but hopefully lives were saved by sounding the alarm. It'll be interesting to read the after-action reports over the next few weeks and see what procedures change.

Surely you jest.

OOC, would you have noticed it if you were cruising underwater in your boomer?

[Nords]

Quote:

Originally Posted by kumquat Surely you jest.

Spouse is a meteorologist/oceanographer who had a long tour at the Joint Typhoon Warning Center, a few more years at PACOM, and nearly three years as a NEPLO. Today she's still a Red Cross shelter volunteer. She's learned a lot about emergency planning and disaster recovery, and I like to stay on top of it. (Our hurricane checklist gets better every year.) At the very least I know how to avoid common mistakes, and at best I can anticipate what Civil Defense or the police are going to do.

Keeping up with the building codes came in handy during our familyroom renovation, too. This room is one step short of a concrete blockhouse, and I'm tempted to stay here during a hurricane rather than evacuate to the shelter of the local elementary school's concrete blockhouse.

Interestingly, Hanauma Bay is closed today due to “unusual tidal fluctuations,” probably left over from the wave action bouncing around between the islands.

Quote:

Originally Posted by kumquat OOC, would you have noticed it if you were cruising underwater in your boomer?

Sonar would have heard the earthquake (certainly narrowband, possibly broadband) for dozens of miles. The tsunami would only be detectable as a very small surface wave and a pressure pulse, and U.S. submarines don't have sensors for those. (Not that I'm aware of, anyway.) You wouldn't feel anything passing down the hull or causing vibrations, either.