Thursday, January 29, 2015

Weird Winter Weather

January 22, 2015

In early fall, sea surface temperature measurements for the eastern Pacific Ocean showed that a large area of unusually warm water was persisting at mid latitudes in the northern hemisphere. Historically unusual, perhaps, but the oceans have been soaking up a lot of heat in the past century, and it's bound to start coming out. Climatologists were also trying to decide if the equatorial Pacific Ocean was going to shift into a recognizable El Nino-Southern Oscillation (ENSO) pattern for surface water temperatures and winds, which also impacts higher latitudes. There had been moderately strong signals for months that an ENSO might start this fall or winter, but thus far this has not developed into a recognizable ENSO pattern.

The emerging seasonal prediction for this winter was that we would have a drier, warmer winter. Well, the warmer part is definitely correct. As for drier, the South Coast has seen a mix of conditions. On one hand, there have been blocks of days to weeks of dry weather. On the other hand, there has been a steady progression of atmospheric rivers, also called Pineapple Expresses, with a tendency to extremely intense rain 'events' or cloudbursts within these storms, as happened just a few weeks ago, when South Bend flooded, and a small creek in Naselle overflowed and blew out a culvert on Highway 4 at the Naselle Youth Camp. Rainfall was around 8 inches at the peak day of the storm, most of which fell in less than six hours.

We depend on consistency in weather patterns, and in seasons. Communities, timberlands, agriculture and outdoor recreation all rely on this consistency. Portland and Seattle metro areas store water reserves in high elevation lakes, which are fed by snow and glacier melt. With dry warm winters, the snowpack they rely on for summer water is not stored in the high Cascades. Regional soils recharge with long winter rains, flowing to streams and rivers for fish habitat and into soils to promote tree and crop growth. In our area, most residents have shallow wells, tapping the upper edge of the highest freshwater aquifer layer on the peninsula. If we don't get enough rainfall to fill local lakes and marshes to overflowing, then the aquifer doesn't recharge in winter. Low snow pack also means poor skiing, which impacts ski resorts in the Cascades and eastward. Major disruptions in winter precipitation affect many aspects of life in the Pacific Northwest. As for recent strandings of sea turtles on local beaches, and lingering brown pelicans, both species are farther north than normal because of that warm water offshore.

This winter has been notable for several atypical weather features:
Mild nights, often around 45 to 50 F, and few cold periods. Temperatures at sea level have rarely dropped below 27 F this winter. Yes, we had light frosts a few nights ago, but no hard frosts, no days to weeks of freezing temperatures or snow on the ground.
Periods of intense rain have occurred several times, when four or more inches fell in just a few hours.
Tornado warnings––now that is really outside the 'normal' box. I don't recall NOAA forecasting a tornado warning for our area at all, until this winter.

A change in the intensity of atmospheric rivers (AR) is another issue. Regional weather records don't go back very far, little more than 170 years in most cases. So it's interesting to look back at historic records for AR, given that as the climate warms, these huge warm storms are expected to intensify, e.g. be larger, last longer, and deliver more warm equatorial water to higher latitudes. Right now, AR deliver around thirty percent of the water that moves from the Equator to high latitudes, and this percentage is expected to increase to fifty percent or more in coming decades.

In the winter of 1861/2 there was a mega-AR, which become the thousand-year-storm standard for the West Coast. Abbreviated 'ARKstorm' (atmospheric river, 1000 years = K, storm), this AR blasted the West Coast from northern Mexico to southern British Columbia for 41 to 47 days. All major rivers flooded along the West Coast. The Los Angeles Basin and Central Valley went underwater, including the newly formed state capital of Sacramento, California. The Columbia and most of its tributaries flooded. Smaller rivers along the coast from northern California to Vancouver Island flooded. We haven't had a thousand-year storm since, but the odds of weather like this coming again, and soon, are likely.

The weather reality for this winter is much warmer air temperatures, with strong storms. Instead of long soaking days of rain, there are intense short bursts of precipitation that flood local streams and swamp communities. It's the new normal. As for the lack of cold weather––find a mesh hat and repellant. The mosquito hatch this spring and early summer should be tremendous. Likewise, slugs and snails will be more numerous, unless there is a very cold period before winter's end.

Safety note: If you do not have a NOAA weather radio at home, get one. Yes, they send out weekly tests, on Wednesdays, usually around noon, and yes, you do have to turn the test off or it stays on for hours. The plus is that you will hear the warnings for thunderstorms, tornadoes, and far-source tsunamis, and other hazard events, directly from the weather service and without any need to use computers or your phone. The radios are inexpensive and work right out of the box. County emergency services and local amateur radio operators can help reprogram them if needed. 

Monday, January 12, 2015

Desmostylia––Ancient Sirenians (Manatees) of the North Pacific

December 11, 2014

This area of southwest Washington and northwest Oregon was underwater for many, many millions of years, which means that marine animals lived here along with fishes and a wide range of invertebrates, even though we do not have fossils from every square mile to look at today. So we look around the Pacific Rim to learn about the diversity of species that formerly lived here.

One of the strangest animals from our watery past is Desmostylia. A chunky, stout aquatic mammal of shallow waters and shorelines, it is distantly related to modern manatees, which are Sirenians. Formerly much more common in geologic time, Sirenians include three living species of manatees, one dugong, and the recently extinct Steller's sea cow. Their closest living relatives are elephants and hyraxes. Fossil Sirenian species in the Desmostylia group lived from the Oligocene to the late Miocene, about 25 million years, ending about 7 mya (millions of years ago). By the Miocene our area was a shallow sea with several river deltas and emerging mountain ranges, and with extensive swamps along the eastern edge, near the position of the modern Cascade Range. Climate was warmer in the Miocene, tropical to subtropical, and sea level was a couple of hundred feet higher.

Desmostylia fossils, including full skeletons and partial bits of bones, teeth and skulls, have been found around the North Pacific, from the south end of Japan, through Siberia, the Aleutian Islands, Pacific Northwest, south to the south tip of Baja California. Teeth make particularly good fossils because they are hard and slow to break down. Desmostylia has interesting large molars, along with more typical mammalian tusks and canine teeth. These teeth have been described as bundles of columns, which gives them their name, from the Greek desmos (bundle) and stylos (pillar).

These mammals were aquatic, and from isotopic analysis of teeth and bones, we know that they were marine. Other marine mammal features include retracted nostrils (tightly closed when underwater), and raised eye sockets (to see better at the surface). Stocky and stout, they weighed up to 440 pounds and were about six feet long, with a heavy shovel-shaped head and large strong teeth, short strong legs, and broad feet. You can see a complete desmostylian skeleton of at the Natural History Museum of Los Angeles County. This individual lived 10 million years ago, towards the end of the Miocene. The museum has also done reconstructions of living animals, to give us an idea of what they were like.

There are no modern analogs to these mammals. For size comparisons, black bears and wild boars (feral pigs) can grow to 400 pounds or more in size. Hippopotamuses weigh up to 3,300 pounds, and live in freshwater, though some populations live in mangrove swamps. Manatees weigh up to 1,300 pounds, and live entirely in water. We could think of Desmostylia as a small hippo, in a sense, though they are not closely related.

With broad grinding molars, Desmostylians were herbivores. In marine and estuarine waters, what did they eat? Sea grasses and seaweeds, including kelps, are the mostly likely food plants. These plants live in shallow saltwater in large, dense stands. There was another powerful reason to stay in shallow water: Megalodon cruised the open waters of the world's warm oceans and seas. Desmostylia were about the right size to this huge shark to be like chicken nuggets to us.

Imagine if today 400-pound, six-feet-long marine herbivores grazed eelgrass beds in Willapa Bay. They'd jostle with the seals for haul out space, or sprawl in the marshes around the edges, and graze down the eelgrass stands at mid to high tide. Water quality might be an issue. Herbivores tend to produce a lot of poop, about five to seven times the volume, based on body size, that carnivores do. Today, hippos are one of the most dangerous animals we live around. Desmostylia might be similarly dangerous––placid until someone gets too close, and then those large teeth come into action, and oops, there's another ex-kayaker or ex-hiker. It would definitely make boating on the bay lively!

For more information, and good reconstructions of Desmostylian, see

Natural History Museum of Los Angeles has great photos of skeletons and animal reconstructions.