During one of my daughter’s recent soccer games in Los Osos, I noticed a nearby flock of brant geese. I learned from one of the parents at the game that John Roser of Los Osos has studied these geese for years. After meeting with John, I discovered some interesting facts.
The brant geese migrate from Arctic nesting sites in northwestern Canada, Alaska and Russia to Morro Bay every fall through spring.
During the fall, the majority of the geese gather at Lzembek Lagoon in southwestern Alaska, near the Aleutian Islands. This lagoon contains some the world’s largest beds of eelgrass, which the geese rely on for food. This staging area allows the geese to add the needed weight and nutrients necessary to complete their migration southward toward Mexico and California. The lagoon supports nearly the entire Pacific Flyway population of brant geese.
When strong low-pressure systems move near the Lzembek Lagoon into the Gulf of Alaska, gale force northwesterly winds develop on the backside of these storms. This provides the tailwinds for the geese as they travel toward Mexico and the western United States. It is believed that when the geese sense these strong tail winds, they take off at night for their lengthy nonstop journey.
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Without the aid of modern navigational devices such as the Global Positioning System, these geese somehow navigate across the vast expanse of the northern Pacific Ocean and often in inclement weather. They clearly have an instinctive sense of direction; some scientists think they possess an internal compass.
In a previous column, I mentioned Weather Station Papa in the middle of the Gulf of Alaska. Observations from this station and a U.S. Air Force facility near the Lzembek Lagoon reveal more interesting facts about the geese. The geese fly at an altitude of about 4,000 feet. Their average true air speed is about 50 mph, but when combined with the gale force northwesterly tailwinds, their speed can exceed 100 mph.
Their spectacular nonstop flight to Mexico or Morro Bay can be accomplished in less than 55 hours, during which the birds can lose more than one-third of their body weight.
Roser explained to me that scientists have learned from banding the geese that brants can live more than 28 years and might migrate more than 11,000 miles annually. Male and female pairs follow the creed “till death do us part” and fly side-by-side, even during the nonstop migratory flights from Alaska to Baja California, Roser said. Families stay together for almost a year while the parents teach their offspring about migration routes and wintering sites, he added.
Until recently, nearly the entire population of Pacific brant geese wintered in Mexico and along the West Coast of the United States, but now as many as 30 percent are opting to spend their winters in Alaska. According to a U.S. Geological Survey study, some scientists speculate that this may be due to a warming climate. Although records are sparse, fewer than 3,000 brant geese were detected wintering in Alaska before 1977. That number now has jumped to as many as 40,000 birds, according to the study.
With so many birds now wintering in Alaska, a sudden and severe cold weather snap could put much of the brant population at risk.
This week’s forecast
A series of Gulf of Alaska storms will continue to move into the Pacific Northwest as a persistent 1026 millibar eastern Pacific high remains about 600 miles west of San Luis Obispo, keeping the storm track to the north of us.
Variably cloudy skies will develop today with dense ground forming in the San Joaquin Valley as a cold front moves into Northern California.
Rain is not expected farther south than the Bay Area.
Today’s high temperatures will range from the low to high 60s throughout the Central Coast with another cool morning forecast on Monday.
High pressure will build over Central and Southern California on Monday, producing northeasterly (offshore) winds. This offshore flow will produce clear and warmer weather, especially at locations closer to the coast through Thanksgiving.
San Luis Obispo might see temperatures reaching the high 70s to the low 80s on Tuesday and Wednesday.
Some of the longer range models are advertising unsettled weather developing by the first part of December as the Eastern Pacific shifts southward.
Surf and sea report
This morning’s 6- to 8-foot (310-degree deep-water) sea/swell (with a 5- to 12-second period) will remain at this height and period through tonight.
A 952-millibar storm with hurricane force winds developed off the Kamchatka Peninsula on Wednesday. Northwesterly (315-degree deep-water) swell from this storm will arrive along our coastline on Monday at 5 to 7 feet (with an 11- to 22- plus second period), building 6 to 8 feet (with a 16- to 18-second period) on Tuesday.
This northwesterly swell will remain at this 6- to 8-foot level but with a gradually shorter period through Wednesday.
During this period, northeasterly (offshore) winds will develop along our coastline. Seawater temperatures will range between 55 and 57 degrees.
Another intense Gulf of Alaska storm will generate a 5- to 7-foot west-northwesterly (285-degree deep-water) swell with a 14- to 22-plus-second period) on Thanksgiving Day, building to 9 to 11 feet (with a 16- to 18-second period) on Friday.
The longer-range models are indicating another intense storm developing in the Eastern Pacific late this week. If this storm develops as expected, potentially large waves from the system are forecast to arrive along our coastline on Dec 1.
Pacific Gas and Electric Co. has a blog called NEXT100.com that provides a look at clean energy and the environment.
John Lindsey is a media relations representative for Pacific Gas and Electric Co. He is also a local weather expert and has lived along the Central Coast for more than 22 years.