Fan and Mortar Geysers are a very infrequent erupting pair of geysers, but when they do erupt, they are extremely impressive. The are not the largest geysers in the world, nor do they output the largest volume of water. They are not the loudest geysers, nor are they the most explosive. Eruptions do not last exceptionally long. They are very infrequent, with an eruption once per every three days at best, sometimes as long as ten days between eruptions. During many seasons they will remain completely dormant with no eruptions at all. And yet, they will be observed constantly for days on end, often even by a few hardcore individuals through the night, just to have a chance to catch an eruption. So why are Fan and Mortar Geysers such a desired eruption? It is all about their structure. Fan Geyser is comprised of at least seven vents. And Mortar Geyser has its own three vents in and around a siliceous sinter cone on the left. Fan and Mortar Geysers are located on a shared geyserite platform along the Firehole River, but far down towards the end of the Upper Geyser Basin of Yellowstone National Park in Wyoming. They are located on the left side of the trail, after crossing the Firehole River, just before Morning Glory Pool, documented in this blog entry, that will sometimes draw visitors this far down and who may just happen to end up in the right place at the right time for an eruption. The odds of this are very low, of course, so usually it requires patience and close observation. While the eruptions can happen as short as three days apart or as long as ten days apart, they are most likely to happen around four to seven days apart, but this is by no means a guarantee. And of course this is assuming that they are active at all. Many summer seasons they will remain dormant for either the entire season or until early to late fall. It is thought that this may happen when the Firehole River is higher and perhaps floods into its underground reservoir, rendering the water too cool to reach the steam flashpoint required for an eruption. By late season, the water level may have receded enough to stop the flooding that hinders the eruption. So if everything is going right for Fan and Mortar Geysers, and they are active, their shared reservoir will slowly fill up and begin to heat up. During these days, they will appear as gently steaming and splashing such as in this phenomenal image of mammatus clouds in a nearby passing storm, taken over the Fan and Mortar geyserite platform during their gently splashing phase, with the Firehole River and a distant ridge also included, available for sale in our store. After the reservoir fills up and heats up, Fan and Mortar Geysers will begin to display cycles of activity, the most notable of which are named the event cycles. The reason these are the most notable is that an eruption of Fan and Mortar Geysers will almost always initiate during an event cycle. The event cycle involves splashing from possibly all seven vents of Fan Geyser, though only four are used to define it. The seven vents of Fan Geyser starting from nearest to the Firehole River are River Vent (nearest the river), High Vent (the highest one), Gold Vent (yellow colored geyserite), Gold 2 Vent (also yellow colored geyserite), Angle Vent (water exits diagonally), Main Vent (the largest), and finally East Vent (the most east or away from the river). The event cycle begins with the start of splashing from River Vent, followed by the start of splashing from High Vent, followed by the start of splashing from Gold Vent, followed by the start of splashing from Angle Vent. If River Vents stops splashing before Angle Vent starts, it is known as a river pause, and if High Vent and Gold Vent stop splashing before Angle Vent starts, it is known as a gold pause. But if both High Vent and Gold Vent continue splashing and reach to heights of at least five feet, it is known as a lock, and the eruption is almost definitely imminent. Within minutes, the entire set of vents in Fan Geyser and Mortar Geyser rise up simultaneously over a large area, with Angle Vent launching water up to and clean over the trail, creating the fan shape that lends its name to the geyser. The view of all vents simultaneously erupting is absolutely breathtaking and worth the effort. The water will hold for several minutes before dying down back into the vents, defining its first pause. Minutes later, all vents will once again simultaneously erupt for several more minutes before dying back down into the vents. It will repeat this for a few more times before transitioning into a short puffing steam phase. In the above photo, The Wild Images Team captures Fan and Mortar Geysers as they begin their initial eruption, with the scene being dominated by the diagonally launched water from Angle Vent, captured at the moment of sunset. The Wild Images Team has captured many other photos in Yellowstone National Park including a Beehive Geyser eruption with a massive rainbow, the world famous Old Faithful Geyser with water textures, a towering Grand Geyser pause burst eruption, a sunset Castle Geyser eruption with a bright rainbow, an afternoon Riverside Geyser eruption with a rainbow, an early morning Lion Geyser eruption with a rainbow, a very difficult to catch Oblong Geyser blue burst eruption, the extremely powerful Artemisia Geyser eruption with deep bursts, the very moment of waves from a Great Fountain Geyser initial eruption, an iconic White Dome Geyser eruption at sunset, the large bursts of a Fountain Geyser eruption in steam, the delicate red light on a Grotto Fountain Geyser eruption at sunset, the defining moment of a Rocket Geyser eruption at sunset, the extremely brief Aurum Geyser eruption with colors, a view through a Cliff Geyser eruption of Black Sand Basin, the colorful patterns of bacterial mats in Midway Geyser Basin, the changing conditions that cause a rainbow to parallel the Snow Lodge, the Biscuit Basin duo of Black Diamond Pool and Opal Pool, the colorfully pock marked waterways of the erupting Blood Geyser, the active steppes of the Mineral Terraces of Mammoth Hot Springs, the distant double rainbow over the Lewis River Canyon, the before eruption reflections of sunset over the terraces of Great Fountain Geyser, the deep colors of sky reflections over Beauty Pool, the thermally induced sunset light filters through the steamy trees, the intense moment of mammatus clouds over the Firehole River, the very early morning fog surrounding Lower Yellowstone Falls, the runoff created reflections over the colorful runoff pan of Constant Geyser, the unworldly terrain of the extensive Porcelain Geyser Basin in Norris, the deeply hued steam over colorful bacterial mat reflections of Grand Prismatic Spring, the contrast of runoff channels surrounding the blue superheated water of Sapphire Pool, differing wave patterns created by the colorful submerged Fishing Cone Geyser, the strong green created by the record depths of mysterious Abyss Pool, the moment the full moon rises over the Grant Village Lakehouse, the cloud symmetry of a sunset reflection over a calm Yellowstone Lake, and moments earlier with a cloud shelf reflection over a calm Yellowstone Lake, each of which are available for sale in our store. Blog posts from Yellowstone National Park have documented the Old Faithful Geyser eruptions, the steamy Oblong Geyser eruptions, the deep drain Uncertain Geyser eruptions, the steep crater Depression Geyser eruptions, the amphitheater Grand Geyser eruptions, the impressive Fan and Mortar Geyser eruptions, the very quick Aurum Geyser eruptions, the rooster tail Whirligig Geyser eruptions, the series type Lion Geyser eruptions, the tall grotto White Dome Geyser eruptions, the frequent Sawmill Geyser eruptions, the double cone Atomizer Geyser eruptions, the nozzled Beehive Geyser eruptions, the cratered Fountain Geyser eruptions, the deep pool Artemisia Geyser eruptions, the playful Vixen Geyser eruptions, the scenic Riverside Geyser eruptions, the very rare Ledge Geyser eruptions from above, the very rare Ledge Geyser eruptions from below, the gurgling Tilt’s Baby Geyser eruptions, the bursts of Great Fountain Geyser eruptions, the hidden Dome Geyser eruptions, the tilted Daisy Geyser eruptions, the remote Pink Cone Geyser eruptions, the long Castle Geyser eruption water phases, the loud Castle Geyser eruption steam phases, the stark Constant Geyser eruptions, the rim wall Cliff Geyser eruptions, the initiation from Grotto Fountain Geyser eruptions, the continuation of Grotto Geyser eruptions, the defining moment of Rocket Geyser eruptions, the marathon Spa Geyser eruptions, the blue waters of a Spouter Geyser eruption, the isolated Artist Paint Pots throwing mud, the little seen intricate burst of a mud volcano, a view of a dozen visitors under a Beehive Geyser rainbow, the eruption through numerous vents of Fan and Mortar Geysers, the enormous amount of water through the runoff channels of Excelsior Geyser, the otherworldly view of cloudy blue runoff pools in the Porcelain Basin, the moment that a large bison bull rolled in his claimed dirt pile, the rule for the right of way wildlife, the high altitudes where a large raven that perches over the Dunraven Pass, the the day that a phoenix streaked across the backcountry sky, the trail from Grant Village that crosses over this suspended bridge, The Wild Images Team in the Grand Canyon of the Yellowstone, our Photographer Jeremy Robinson shadowed in Morning Glory Pool, and The Wild Images Team Travel Gnome at the Yellowstone National Park entrance sign.
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