Tracy Arm
| Tracy Arm | |
|---|---|
 Whaler from NOAA Ship John N. Cobb with Sawyer Glacier in the background. | |
  Tracy Arm Location of the fjord | |
| Location | Alaska, USA |
| Coordinates | 57°54′41″N 133°24′08″W / 57.91139°N 133.40222°W |
| Type | Fjord |
| Basin countries | Alaska |
| Max. length | over 30 miles (48 km) |
| Location | |
 Interactive map of Tracy Arm | |
Tracy Arm is a fjord in the U.S. state of Alaska near Juneau (outlet at 57° 46' 40" N 133° 37' 0" W). It is named after Secretary of the Navy Benjamin Franklin Tracy (1889-93). It is located about 45 miles (72 km) south of Juneau and 70 miles (110 km) north of Petersburg, Alaska, off of Holkham Bay and adjacent to Stephens Passage within the Tongass National Forest. Tracy Arm is the heart of the Tracy Arm-Fords Terror Wilderness, designated by the United States Congress in 1990.
Tracy Arm-Fords Terror Wilderness contains 653,179 acres (2,643.32 km2) and consists of two deep and narrow fjords: Tracy Arm and Endicott Arm. Both fjords are over 30 miles (48 km) long and one-fifth of their area is covered in ice. During the summer, the fjords have considerable floating ice ranging from hand-sized to pieces as large as a three-story building. During the most recent glaciated period, both fjords were filled with active glaciers
On August 10, 2025, a large landslide occurred in the fjord, generating a megatsunami with a height on land of 481 m (1,578 ft).[1] As of 2026[update] this was the second highest tsunami in recorded history.[2]
Access
[edit]The most common access is by boat using Stephens Passage and entering Holkham Bay and Tracy and Endicott Arms. Float planes from Juneau and Petersburg are also used as a means of access. Large tour vessels and smaller commercial cruise boats frequently use Tracy Arm as a tour destination or as a stop along their normal tour routes.
Sawyer Glacier
[edit]The twin Sawyer Glaciers, North Sawyer and South Sawyer, are located at the end of Tracy Arm.[3] The wildlife in the area includes black and brown bears, deer, wolves, harbor seals, and a variety of birds, such as Arctic terns and pigeon guillemots. The mountain goats, which are usually found in the higher elevation areas, have been seen near the base of Sawyer Glacier.[4][5]
Deepwater emergence
[edit]
The deep passageways and thin continental shelf leads to unique connections between offshore and inshore waters. The colder water temperature, nutrient-rich upwelling, and strong currents allow for many species that live in deeper water to survive in the shallower waters.[6]
The corals in this area, such as Primnoa pacifica, have contributed to the location being labeled as Habitat Areas of Particular Concern.[7] P. pacifica is typically a deep water coral normally found between 150 metres (490 ft) and 900 metres (3,000 ft); however, in the Tracy Arm it is found between 20 feet (6.1 m) and 100 feet (30 m), offering a unique opportunity for research.[6]
2025 megatsunami
[edit]At 05:26 local time (13:26 UTC) on 10 August 2025 a rockslide caused a megatsunami, found on later analysis to have had a runoff height of about 481 m (1,578 ft).[8][1] The area is visited in daytime by tourist cruise ships, which would have been devastated by a tsunami at a later hour.[9]
Huge megatsunamis are caused by landslides into water; unlike many ocean tsunamis they are usually localised and dissipate quickly. Research suggests that glacier melt driven by climate change[1] is making such collapses far worse. The only known higher megatsunami occurred in 1958 in Lituya Bay, Alaska, a region especially prone to megatsunamis because of its steep mountains, narrow fjords and frequent earthquakes.[1][9]
References
[edit]
- ^ a b c d Shugar, Dan H.; Barnhart, Katherine R.; Berdahl, Mira; Caplan-Auerbach, Jacqueline; Ekström, Göran; Fathian, Aram; et al. (May 6, 2026). "A 481-meter-high landslide-tsunami in a cruise ship–frequented Alaska fjord". Science. doi:10.1126/science.aec3187. ISSN 0036-8075.
- ^ West, Michael; Karasözen, Ezgi. "Alaska's near‑record landslide tsunami sent a wave 1,580 feet up the fjord walls – and left clues for building a warning system". The Conversation. Retrieved May 7, 2026.
- ^ Lynn, Readicker-Henderson (2006). Adventure Guide Inside Passage & Coastal Alaska. Hunter Publishing, Inc. p. 241. ISBN 1-58843-515-6.
- ^ "Sawyer Glacier". Norwegian Cruise Line. Archived from the original on October 14, 2002. Retrieved June 11, 2007.
- ^ "Adventure Bound Alaska". Weber. Retrieved June 11, 2007.
- ^ a b Waller, RG; Stone, RP; Mondragon, J; Clark, CE (2011). "Reproduction of Red Tree Corals in the Southeastern Alaskan Fjords: Implications for Conservation and Population Turnover". In: Pollock NW, ed. Diving for Science 2011. Proceedings of the American Academy of Underwater Sciences 30th Symposium. Dauphin Island, AL: AAUS; 2011. Archived from the original on March 5, 2016.
- ^ Stone Robert P; Shotwell S Kalei. (2007). "State of deep coral ecosystems in the Alaska Region: Gulf of Alaska, Bering Sea and the Aleutian Islands" (PDF). In: Lumsden SE et Al., Eds. The State of Deep Coral Ecosystems of the United States. NOAA Technical Memorandum CRCP-3. Silver Spring, MD: 65–108. Retrieved March 11, 2013.
- ^ Alund, Natalie Neysa (May 7, 2026). "Alaska's 1,578-foot tsunami was second largest ever recorded". USA Today. Retrieved May 8, 2026.
- ^ a b Stephens, Kate; Briggs, Helen; Church, Kevin (May 6, 2026). "Massive Alaska megatsunami was second largest ever recorded". BBC News.
| International | |
|---|---|
| National | |
| Other | |
- Bodies of water of Hoonah–Angoon Census Area, Alaska
- Bodies of water of Juneau, Alaska
- Fjords of Alaska
- Landforms of Hoonah–Angoon Census Area, Alaska
- Landforms of Juneau, Alaska
- Glaciers of Alaska
- Glaciers of Hoonah–Angoon Census Area, Alaska
- Glaciers of Juneau, Alaska
- Protected areas of Hoonah–Angoon Census Area, Alaska
- Protected areas of Juneau, Alaska
- Tourist attractions in Juneau, Alaska
- Wilderness areas of the Tongass National Forest
- Glaciers of Unorganized Borough, Alaska