Firehole Lake Drive
Firehole Lake Drive is a one-way paved road through a section of the Lower Geyser Basin. To reach it, drive 6.8 miles north of the Old Faithful Interchange, or 9.3 miles south of Madison Junction on the Old Faithful to Madison section of the Grand Loop Road. It is located in between two other thermal areas, with the Fountain Paint Pots to the north and the Midway Geyser Basin to the south.
The first feature along the Firehole Lake Drive is the Firehole Spring, accessed from the first long pullout on the left side.
A short way down the road is the next parking area on the left, this one for Surprise Pool. This pool was named because early visitors used to throw sand into the pool to cause “surprise boiling.” This action is damaging, and illegal today, so don’t try it. This pool has a much deeper blue color than most other pools.
Great Fountain Geyser
Just beyond Surprise Pool is the Great Fountain Geyser. The eruptions of this geyser average over 100 feet, with occasional super eruptions going over 200 feet. The interval between eruptions is 10-14 hours, so actually seeing this can be difficult to plan. However, once the eruption does start it typically lasts 45-60 minutes. The pool overflows and boils violently when an eruption is imminent. A picture of the cone area is to the left.
White Dome Geyser
Further down the road, but easily visible from the Great Fountain Geyser, is the massive cone of White Dome Geyser. This enormous buildup shows that this geyser has been around for a long time, and it has nearly sealed itself closed. Eruptions are around 30 feet high, and usually last only a minute or so. They are normally frequent, every 15-30 minutes, but occasionally take much longer to recharge.
Pink Cone Geyser
The next feature along the road is the Pink Cone Geyser. This geyser erupts around 30 feet high, with a duration as short as 30 minutes and as long as 3 hours. The interval varies widely, but is usually at least 6 hours. Occasionally it can take as long as 20 hours to recharge, and historically it has been as long as 2 days.
The road continues alongside a lake before cutting back towards to Grand Loop Road. A parking area is at the bend for several features. The first of these is the big lake on the right, the namesake of the road, Firehole Lake. This is the largest hot spring in this area. Large mats of warm water bacteria, called thermophiles, lie underneath, creating the unusual brown color.
Across the road from Firehole Lake is another large lake, named Black Warrior Lake. On the edge of the lake is Steady Geyser, shown to the left. Manganese oxide emitted from this geyser accounts for the dark color of Black Warrior Lake.
Toward the end of the boardwalk along Black Warrior Lake are the Hot Cascades. This is a very small waterfall area where the hot water from Black Warrior Lake drops down into Hot Lake below, on the other side of the boardwalk.