HYDROARC
The U.S. long-range warning series for the Arctic Ocean.
HYDROARC warnings cover Arctic waters. The series is much smaller than HYDROLANT or HYDROPAC, and its volume follows the season: most messages concern summer survey work, scientific moorings and ice-season operations in the Beaufort, Chukchi and other Arctic seas.
Five Arctic NAVAREAs (XVII to XXI) were added to the World-Wide Navigational Warning Service in 2011 as shipping in the region grew; HYDROARC messages often cite the same dangers those coordinators broadcast.
What the archive shows
1,169 messages in this archive use “HYDROARC”, the earliest issued 2010-07-02 and the latest 2026-09-16. 1 of them is in force in the latest lists we collected. A hazard reported again and again counts once per message.
The largest yearly count is 2014, with 121 messages. Collection is incomplete between 2024-05 and 2026-08-17, so 2024, 2025 and 2026 are not comparable with fully collected years.
Other accounts for 734 of 1,169 recorded messages (63%), the largest warning type group in this selection.
Located messages that use it fall in 16 sea areas; the most frequent are Barentsz Sea (107), Kara Sea (35) and Arctic Ocean (30).
Messages that use it are issued most often in September (251 across all years) and least often in January (20).
By warning series: HYDROARC 1,167, HYDROLANT 1 and HYDROPAC 1.
Messages using it, by year of issue
By month of issue, all years
Where it appears · 16 sea areas
In force now · 1
- HYDROARC 191/26 · Surveys · Norwegian Sea2026-08-28 · in force
…64-33.50N 006-04.80E, 64-32.70N 004-33.70E. SEVEN MILE BERTH REQUESTED. 2. CANCEL HYDROARC 190/26.
Survey operations in progress until further notice by M/V amazon conqueror towing 12 10000 meter long cables… →
How it reads in recent messages
- HYDROARC 238/26 · Nav aids · Beaufort Sea2026-09-16
…SEA. CANADA. 1. LIGHT AT SHINGLE POINT 69-00.00N 137-34.00W INOPERATIVE. 2. CANCEL HYDROARC 198/22.
Light at shingle point 69-00.00N 137-34.00W inoperative → - HYDROARC 237/26 · Nav aids · Beaufort Sea2026-09-16
BEAUFORT SEA. CANADA. 1. LIGHT AT PITT ISLAND 69-09.00N 136-11.00W INOPERATIVE. 2. CANCEL HYDROARC 145/25.
Light at pitt island 69-09.00N 136-11.00W inoperative → - HYDROARC 236/26 · Nav aids · Beaufort Sea2026-09-16
…CANADA. 1. RACON AND LIGHT AT PELLY ISLAND 69-37.00N 135-29.00W INOPERATIVE. 2. CANCEL HYDROARC 227/26.
RACON and light at pelly island 69-37.00N 135-29.00W inoperative → - HYDROARC 206/26 · Exercises · Barentsz Sea2026-09-02
…033-36.00E, 70-12.00N 035-30.00E, 69-34.50N 035-30.00E, 69-34.50N 033-36.00E. 2. CANCEL HYDROARC 203/26. 3. CANCEL THIS MSG 102000Z SEP 26.
Hazardous operations 0500Z to 1900Z daily 05 thru 10 sep in area bound by 70-12.00N 033-36.00E, 70-12.00N… → - HYDROARC 187/26 · Wrecks · Kara Sea2026-08-26
…D. 9.9 METERS IN 71-51.54N 082-33.59E. E. 6.4 METERS IN 71-51.02N 082-34.85E. 2. CANCEL HYDROARC 186/26.
Depths reported: a. 12.3 meters in 71-53.99N 082-35.35E → - HYDROARC 168/26 · Missiles · Barentsz Sea2026-08-12
…029-27.88E, 73-01.54N 030-54.23E, 71-53.17N 032-54.86E, 71-39.58N 031-25.22E. 2. CANCEL HYDROARC 161/26. 3. CANCEL THIS MSG 271900Z AUG 26.
Hazardous operations, rocket launching 132100Z to 132359Z, 0001Z to 1800Z and 2100Z to 2359Z daily 14 thru… → - HYDROARC 62/24 · Other2024-04-26
ARCTIC. EAST SIBERIAN SEA. RUSSIA. DNC 27. CANCEL HYDROARC 52/24 AND THIS MSG.
Cancel HYDROARC 52/24 and this msg →
Earliest in the archive
- HYDROLANT 1238/10 · Other2010-07-01
…BROADCAST WARNINGS WITHIN THE ARCTIC OCEAN REGION. THESE WARNINGS WILL BE ISSUED AS A HYDROARC. ALL AMSI MSGS WILL REMAIN IN EFFECT UNTIL CANCELLED BY THE CORRESPONDING HYDROARC. 3.…
The international maritime organization (imo), the international hydrographic organization (iho) and the… →
Often in the same message
Related terms
- NAVAREA
- One of the 21 ocean areas of the World-Wide Navigational Warning Service, each with a coordinator that broadcasts long-range warnings.
- HYDROLANT
- The U.S. long-range warning series for Atlantic waters outside NAVAREA IV, including the eastern Atlantic, the Mediterranean and adjoining seas.
- HYDROPAC
- The U.S. long-range warning series for the Pacific outside NAVAREA XII and for the Indian Ocean, Persian Gulf and adjoining seas.
- Scientific mooring
- Instruments anchored to the seabed and held up by floats, sometimes just below the surface, left for months to measure the ocean.
Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.