Tsunami Recap - March 11, 2011

After the earthquake in Japan, we closely watched the NOAA Tsunami Advisories 
issued for Long Beach. The forecast was for the tidal surge to arrive about 
0832 LT. We also found monitoring the NOAA Ports Real-Time Water level for Los 
Angeles helpful. We started seeing significant tidal flow just about 0940 LT. 
The amplitude actually increased during the first 12 hours, reaching almost 3 
feet. The current “period” was about 20- 30 minutes – we easily had currents 
of over 6 knots. The currents were variable with eddys setting up at choke 
points throughout the harbor. The most obvious flow was in and out of the 
middle harbor and this was met by a current flowing through the LA Harbor 
entrance through the Cerritos Channel out the back channel, which created 
significant currents middle harbor and back channel. 

The pilots moving ships during the first 14 hours encountered challenges at 
the breakwater entrance turning into the channel as well as leaving the 
channel for the anchorage. The back channel with the significant flow was also 
challenging. A pilot reported a speed of 1.8 kts inbound past LB121 on a 7 
knot dead slow bell due to current. We evacuated two tankers prior to the 
tidal surge arriving; one from D-6 and one from LB 121 between 0445 and 0615 
LT on the 11th.

Due to the variable and unpredictable currents we held an ATC tanker out of 
the harbor scheduled for LB121 for 20 hours. We put an additional tug on this 
ship for docking. The Tsunami tidal surge took 18- 20 hours until we to 
started to notice a reduced amplitude and a full 36 hours until the flow 
reduced to insignificant levels.

Mark Coynes
Jacobsen Pilot Service, Inc.