The Upper Geyser Basin...

The world-famous and uber-popular Old Faithful Geyser sits in the Upper Geyser Basin (UGB), at an altitude of 2240m, in a high point of the supervolcano caldera, and in the south-west quarter of Yellowstone National Park, bisected by the Firehole River. In this spectacular zone of hydrothermal activity, Old Faithful is itself nothing special, it is not the tallest or largest, but it is very regular in its eruption schedule, and the 1900 vintage Old Faithful Lodge is positioned right in front of it.

Old Old Faithful Inn is the classic accommodation choice in Yellowstone, but it's only open in summer.

Between eruptions, Old Faithful puffs steam, sometimes not so much.

One look at Old Faithful, and you just have to wonder what is underneath! What arrangement of plumbing causes its eruptions? Why are they regular? Why are they not perfectly regular? Numerous formal and hand-written signs predict the time of Old Faithful's next eruption, and the claimed accuracy is plus or minus 10 minutes. We couldn't really establish where these predictions come from, and in particular, whether the prediction for the next one is dependent on the actual time of the previous eruption or how long it lasted. But there is ample historical data available. Intervals between eruptions have been between 40 and 125 minutes for 20 years. There's a bimodal distribution of waiting times, with one cluster covering 45-60 minutes, the other 70-90 minutes, and, significantly, longer waiting times produce longer eruptions, (2 and 4.5 minutes respectively). Average waiting times are slowly getting longer - it was 66 minutes in 1939, but nowadays it is a highly predicatble 90 minutes. It's said that this slow-down is partly due to "abuse" by visitors throwing stuff into the geyser's vent. Early visitors did their laundry in the vent!

Crowds gathered as the predicted time for an Old Faithful eruption approaches.

A kind passer-by took this pic of us waiting for the next scheduled eruption of Old Faithful.

This pine, said to be the most photographed tree in the Park, gives scale to steam venting from Old Faithful Geyser.

Old Faithful's eruptions are quite modest compared to others. Boilng water shoots vertically up to 30-60m in the air, and then steam blows off according to the wind direction. We saw other impressive eruptions in the Upper Geyser Basin - one was at a distance from Grand Geyser, the tallest predictable geyser (60m every 7 to 15 hours), and the other was Castle Geyser (25m every 10-12 hours) where we were on the spot!

Grand Geyser has the largest cone in the Upper Geyser Basin.

Near Castle Geyser, a footbridge crosses the Firehole River.

Castle Geyser only erupts twice a day. It has the broadest cone of any geyser in the Upper Basin.

Thus we discovered that Old Faithful's eruptions were not that spectacular. Steam is venting all the time, with the intensity increasing at the eruption. Stand in the wrong place and the wind blown steam plume can obscure the eruption altogether! So, to capture something different, we decided to try some eruption photography at night. There is no lighting on the geyser, so exposure times were 30 seconds, and hands were frozen. Standing to the east of the geyser, with a moderate wind from the north, the steam plume creates a magical fan from right to left. The view is almost the same during the eruption, except the vertical blast of boiling water comes starkly into focus. And we even caught some shooting stars!

The vertical eruption of boling water is clear, then the extra steam is blown away by the wind.

Like a boiling kettle, Old Faithful emits steam between eruptions. Here, a few minutes away from an eruption, steam is taken off by the wind.

Yellowstone National Park has about 10,000 geothermal features, with the highest concentration in the UGB which boasts a network of boardwalks allowing us to walk around in relative safety (people have did getting to close to thermal activity, and as mentioned in our previous blog post, the boardwalk did not protect us from being harassed by bison). Several walks around were very worthwhile with there being many photogenic sights to be seen, as our images will attest. Starting early in the morning, it was -23C, so rather chilly!

We walked all around this region of the Upper Geyser Basin as far as the Morning Glory Pool.

Old Faithful geyser venting steam as it builds up to an eruption.

Eerie and mysterious is this artistic mudpot in the Upper Geyser Basin.

Looking towards the morning sun in the Upper Geyser Basin of Yellowstone National Park.

Many hot springs in the Upper Geyser Basin are named, not sure what this pretty one is called. Castle Geyser can be seen in background left.

Under threatening skies at dawn, bubbling pools and springs of the Upper Geyser Basin drain into the Firehole River.

Hot water from Liberty Pool flows into the Firehole River.

Early morning view over a vent in the Upper Geyser Basin.

Appearing to have twin vents, the Riverside Geyser sits right on the edge of the Firehole River.

Good temperature for a brisk walk around the Upper Geyser Basin.

In the UGB, there over 500 hydrothermal features, of which 130 are named, but one most interesting is Morning Glory Pool which used to be beside the main road to Old Faithful, and thanks to its convenient access, suffered vandalism, blocked vents and cooling from thrown-in trash. Vandalism was eventually controlled by relocating the road!

This bison near Norris Pool seems to like the warmth of the Yellowstone thermal activity, but possibly there is just less snow there, and it's easier to forage.

This bison ponders crossing the Firehole River near Morning Glory Pool, but soon decides against it, and wanders into the scrub.

Beautiful Morning Glory Pool was named in the 1880s but its proximity to the then road led this beautiful pool to suffer vandalism where coins, trash, rocks, and logs were thrown in, contaminating it and blocking its vents, cooling it. Yellow is bacteria that formerly coloured only the periphery of the spring now spreads toward its center. The road was moved away from Morning Glory to save it.

We stayed two nights at the Old Faithful Snow Lodge (1999), about 100m from the geyser and which, although recent, is designed in a classically opulent lodge style. With the Mammoth Hot Springs Hotel closed for renovations, the Snow Lodge is the only accommodation open within the park in winter. Accordingly, it was crowded woth groups like ours and individuals, and the one restaurant was hard to get seated in. Despite its name, the Snow Lodge is open year round. We had a very comfortable ground floor room, no TV, facing out to an ice skating rink.

Our abode for two nights was the Old Faithful Snowlodge (1999)

Warming up in the cosy Firehole Lounge in the lobby area of the Snowlodge.

Big carpark and a flyover make for a terrifying vision of Old Faithful in summer!

More Yellowstone images here.