Winter Solstice

The winter solstice will occur at 18:19HST today.

Sunrise over Georgia Strait
Sunrise over Georgia Strait

The Sun has reached the most southerly declination it will achieve this year. After today the Sun begins to move north in our skies.

Today will be the shortest day of the year for those of us located in the northern hemisphere.

Today is considered the start of winter for most cultures in the northern hemisphere, or the start of summer for those in the southern hemisphere.

2019 Apsides and Seasons
Event Universal TimeHawaii Standard Time
Perihelion Jan 0305:20UTJan 0219:20HST
Spring Equinox Mar 2021:58UTMar 2011:58HST
Summer SolsticeJun 2115:54UTJun 2105:54HST
Aphelion Jul 0422:11UTJul 0412:11HST
Fall Equinox Sep 2307:50UTSep 2221:50HST
Winter SolsticeDec 2204:19UTDec 2118:19HST
Data from US Naval Observatory Data Services

Winter Solstice

Winter solstice occurs today at 16:28HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2017 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 14:18UT Jan 4 04:18HST
Vernal Equinox Mar 20 10:29UT Mar 20 00:29HST
Summer Solstice Jun 21 04:24UT Jun 20 18:24HST
Apehelion Jul 3 20:11UT Jul 3 10:11HST
Autumnal Equinox Sep 22 20:02UT Sep 22 10:02HST
Winter Solstice Dec 21 16:28UT Dec 21 06:28HST
Source: USNO data Services

 

Winter Solstice

Winter solstice occurs today at 00:44HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2016 Solstices and Equinoxes
  UT HST
Perihelion Jan 2 22:49UT Jan 2 12:49HST
Vernal Equinox Mar 20 04:30UT Mar 19 18:30HST
Summer Solstice Jun 20 22:34UT Jun 20 12:34HST
Apehelion Jul 4 16:24UT Jul 4 06:24HST
Autumnal Equinox Sep 22 14:21UT Sep 22 04:21HST
Winter Solstice Dec 21 10:44UT Dec 21 00:44HST
Source: USNO data Services

 

Winter in Hawaii

Rain Gauge
A rain gauge indicating over three inches of rain
I does look like we will have a white Christmas here on the Big Island. Yes it snows in Hawaii, at least atop our nearly 14,000ft mountains.

It is currently snowing with freezing fog at the summit. The morning ranger report noted that there are blizzard conditions on the summit and that the road was impassable. The road is closed to all vehicles (not just the public) and the snow removal crews will not attempt to clear the road today. I am scheduled to go up tomorrow, I do have a few things I would like to get done, this may not happen.

Continue reading “Winter in Hawaii”

The Storm Continues

All day the storm atop our mountain continued. As we watched in the cameras the snow fell heavily, often so thick nearby structures disappeared into the white. Unlike yesterday the winds have eased, the snow quickly accumulates where it falls instead of drifting against the structures. As we watch through the day things began to vanish, railings and guardrails buried in the snow.

Mauna Kea Blizzard
A snowstorm continues for a second day atop Mauna Kea, December 2, 2016
The snowplow crews made it to the summit, if only briefly. One pass on the summit ridge near UKIRT could be seen in the cameras as the snow plow passed by. As quickly as they cleared the road the storm again covered it with white. The crews soon realized the futility and retreated down the mountain. They will not even attempt to try tomorrow as the forecast remains dire. They will next attempt to clear the road on Sunday.

Observing is, of course, cancelled.

Continue reading “The Storm Continues”

Winter is Here

Today marks the beginning of winter. While snow and ice can appear on the summit of Mauna Kea any time during the year, the most severe weather usually occurs during winter storms. We all look forward to the beautiful sight of Mauna Kea with her white coat. Of course this comes at a price, days of difficult access to the summit facilities, or no access at all. The loss of observing nights due to ice and clouds is most common from January to March.

Iced
The emergency evacuation vehicle covered with ice

Winter Solstice

Winter solstice occurs today at 18:48HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2015 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 08:59UT Jan 3 22:59HST
Vernal Equinox Mar 20 22:45UT Mar 20 12:45HST
Summer Solstice Jun 21 16:38UT Jun 21 06:38HST
Apehelion Jul 6 12:59UT Jul 6 02:59HST
Autumnal Equinox Sep 23 08:20UT Sep 22 22:20HST
Winter Solstice Dec 22 04:48UT Dec 21 18:48HST
 
Source: NASA Sky Calendar

 

White Mountian

A great deal of mythology swirls about our mountain. Some of it may be true, much is probably not as wishful thinking and reality collide on the summit. The current debates have moved every little detail into the light.

Mauna Kea White
Mauna Kea with a fresh covering of snow and ice
One of the claims I have heard repeated a few times recently is that in the past Mauna Kea always had snow, even in summer, making the name “White Mountain” very applicable.

I had my doubts about this. Whenever these questions arise it is important to check the records. Fortunately this has already been completed for us… Norbert Schorghofer, Elianna Kantar, and M. Puakea Nogelmeier at the University of Hawaii combed through the historical records looking for observations of the presence of snow atop Mauna Kea. What they found is that there were any number of records indicating the lack of snow on the mountain.

Follow the link and read the paper, it is a fascinating view into the past of Mauna Kea. Included are excerpts from ships logs and diaries of early visitors to the islands. At the end is a convenient timeline of the accounts covering the first century of written records and a set of three conclusions drawn from this information. The author’s conclusion is clear, Mauna Kea has not featured permanent snow cover any time in the last few centuries.

There was a time when the mountain featured permanent snow and ice fields. During the last ice age, around 12,000-11,000 years ago, there was permanent ice and active glaciers in the summit region. Along the access road there are textbook glacial features to be seen, glacial polish and moraines. This was gone before humans arrived in the islands. What we see today was probably much as it was over the past few centuries, as borne out in the records of the first European voyagers to make it to the islands. Snow may have been more common, but there were certainly periods when no snow was to be seen atop the summit of Mauna Kea.

These historical accounts date from long before human activities had begun dumping vast quantities of carbon dioxide into the atmosphere. We do face an uncertain climate future, warming temperatures may reduce snowfall. The opposite may also be possible, warmer sea surface temperatures may create more precipitation at the summit with heavier snowfall events possible.

Winter Solstice

Winter solstice occurs today at 13:03HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the Latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere. Alternately, this is the first day of summer for those folks in the southern hemisphere.

2014 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 05:59UT Jan 3 19:59HST
Vernal Equinox Mar 20 16:57UT Mar 20 06:57HST
Summer Solstice Jun 21 10:52UT Jun 21 00:52HST
Apehelion Jul 3 22:59UT Jul 3 12:59HST
Autumnal Equinox Sep 23 02:30UT Sep 22 16:30HST
Winter Solstice Dec 21 23:03UT Dec 21 13:03HST
 
Source: NASA Sky Calendar

 

The First Storm of Winter on Mauna Kea

It is currently snowing on the summit. Not just a dusting this time, but a real blanket of white on the mountain. Poli Ľahu has returned to the summit. The forecast is calling for up to three inches of white before tomorrow morning.

We just got word that the Keck summit crew is abandoning the summit. They are leaving before the conditions get worse.

A photo from a UKIRT webcam is below. I would post one from our Keck cameras, but the camera windows are covered with blown snow and ice. I have a new all-weather webcam, a full pan-tilt-zoom unit to install, but it is still sitting in a box at the summit. Personally I am not planning being up until Wednesday, I wonder if the snow will still be there, fresh snow on the mountain is always pretty.

Snow on Mauna Kea
The first winter storm on Mauna Kea for the 2014-2015 season blankets the summit in white.