Editing Island Park, Idaho (section)

===Regional geography===
The area was known as Island Park long before the {{convert|33|mi|km|adj=on}}-long town was incorporated.<ref>Dean H. Green, A History of Island Park, 1990, p. 6.</ref> The area known as Island Park is mostly a large crater or [[caldera]] named the [[Henry's Fork Caldera]] that was created by the same [[Yellowstone hotspot|hotspot]] that created the earlier [[Island Park Caldera]] and the later [[Yellowstone Caldera]].<ref>{{cite web |title=Yellowstone map |url=https://pubs.usgs.gov/fs/2005/3024/press-images/fig_03_yellowstone_map.jpg |website=USGS Publications Repository |access-date=14 May 2020}}</ref>
[[Image:IP Place Names.jpg|left|thumb|250px|Upper [[Henrys Fork (Snake River)|Henrys Fork]] drainage]] 
In addition to the portion which lies on the Henry's Fork Caldera, about a third of what is known as Island Park is north of the caldera, extending across Henry's Lake Flat and Henry's Lake towards the Idaho/Montana border. Henry's Lake Flat is a flat bottomed valley between high mountain ranges, with [[Henrys Lake]] at the northwest end of the flats.  [[Mount Jefferson (Bitterroot Range)|Mount Jefferson]], south of Henry's Lake, is {{convert|10203|ft}} high and Targhee Peak, north of Henrys Lake is {{convert|10240|ft|0}} high. The most famous of Island Park's peaks, however, is the {{convert|9886|ft|m|adj=on}} [[Sawtell Peak]], south of Henrys Lake near Mount Jefferson. The peak is known for its beauty and is named for a perceived resemblance to a [[Native Americans in the United States|Native American]] chief's profile while napping. The peak has also been called Chief Rains in the Face. Sawtell Peak is topped by a [[FAA]] radar dome and is visible from nearly anywhere in Island Park.

Although much smaller than either the Island Park Caldera or the Yellowstone Caldera, the Henry's Fork Caldera is still one of the largest calderas in the world and is the only large caldera in the Yellowstone region that is plainly visible.<ref>Wood and Kienle, 1990, Volcanoes of North America: United States and Canada: Cambridge University Press, 354p., p.263-267</ref>  It has a nearly level {{convert|20|mi|km|adj=on}} wide circular floor that slopes slightly towards the southeast. The caldera floor is at about {{convert|6000|ft|-1}} of [[elevation]] with the rim generally being several hundred feet higher. The Henry's Lake Flat area, north of the caldera, is a little higher. Henry's Lake sits at about {{convert|6500|ft|-1}}, with the flats sloping slightly southward towards the caldera.

The Island Park area is mostly forested with many meadows and grasslands. It is mostly level, but is surrounded by forested hills and high mountains in the north. The [[Henrys Fork (Snake River)|Henrys Fork]] of the Snake River meanders through Island Park with its headwaters at Henry's Lake and at [[Big Springs (Idaho)]]. The Henry's Fork is impounded by [[Island Park Dam]] to form Island Park Reservoir outside the north rim of the caldera. In fact, the entire south bank of Island Park Reservoir is formed by the northern slope of the caldera. The Henry's Fork crosses through the caldera and then cascades off from it at [[Upper Mesa Falls|Upper and Lower Mesa Falls]].

[[Image:JeffersonFlowers.jpg|right|thumb|200px|[[Mount Jefferson (Bitterroot Range)|Mt. Jefferson]] and [[Castilleja|Indian Paintbrush]]]][[File:Meadow in Island Park, Idaho.jpg|right|thumb|200px|Meadow in Island Park revealing flat bottom of caldera floor, [[Teton Range]] in background]]
The geography of Island Park is actually unique and distinctive. It is largely flat and it has unusually high precipitation. Island Park is at the same {{convert|6000|ft|-1}} elevation as Teton Valley, Idaho, Jackson Hole, Wyoming, or the Centennial Valley, Montana; yet while these nearby areas are semi-arid prairie or even desert areas receiving less than {{convert|12|in|cm}} of precipitation annually, Island Park is forested and green with many streams, ponds, lakes, and meadows. Island Park receives well over {{convert|30|in|cm|0}} of precipitation annually, with parts receiving over {{convert|50|in|cm|0}}. That is, Island Park has three times the rainfall and snowfall as nearby areas of the same elevation.<ref>NOAA annual precipitation map maker http://nationalatlas.gov/natlas/Natlasstart.asp {{Webarchive|url=https://web.archive.org/web/20081211122853/http://nationalatlas.gov/natlas/NatlasStart.asp |date=2008-12-11 }}</ref>

The [[Snake River Plain]] that was also formed by the Yellowstone [[hotspot (geology)|hotspot]] aligns with the gap between the [[Sierra Nevada (U.S.)|Sierra Nevada]] and [[Cascade Range|Cascade]] mountain ranges along the [[West Coast of the United States]] so that there is a [[Snake River Plain#Effects on climate|moisture channel]] that extends from the distant [[Pacific Ocean]], between the Cascades and Sierra Nevada, through the [[Rocky Mountains]] to Island Park.

This abundant precipitation in Island Park falls on the relatively level floor of the caldera, where it forms numerous meandering streams, ponds, marshes, and meadows. It also falls on the higher areas to the east along the Yellowstone Park border, where it percolates though the granular volcanic deposits to emerge as some of the largest springs in the world. [[Big Springs (Idaho)|Big Springs]], Buffalo River Springs, and Warm River Springs all are [[Spring (hydrosphere)#Classification|1st Magnitude springs]], and they form some of the crystal-clear meandering streams that the area is famous for.