Obstruction Reef - Pacific Northwest
Obstruction Reef, up in the Pacific Northwest, isn't your typical tropical coral show, but it’s got its own rugged appeal. We’ve found it’s a spot that truly shines during late spring and early summer when the herring and eulachon run. The action can be incredible then, with gray whales often patrolling the deeper edges, and you’ll see the sea floor carpeted with sunflower stars and those big geoducks. The currents here can push you around a bit, especially on a stronger tide, so it’s definitely a dive for those comfortable with a bit of a ride. Expect to see some hefty California spot prawns and maybe even a giant octopus tucked into a crevice if you look closely.
- Location
- Pacific Northwest, United States, North America
- Coordinates
- 49.842800, -127.096280
- Type
- reef
Best Time to Dive in Pacific Northwest
The warmest water temperatures in Pacific Northwest occur in August, averaging 16.5°C (up to 15.6°C). The coolest conditions are in February at 6.9°C.
Monthly Water Temperatures
- January: 7.1°C (air: 6.3°C)
- February: 6.9°C (air: 4.5°C)
- March: 7.7°C (air: 6.6°C)
- April: 9.5°C (air: 8.7°C)
- May: 12.0°C (air: 11.7°C)
- June: 14.0°C (air: 13.7°C)
- July: 15.7°C (air: 14.9°C)
- August: 16.5°C (air: 15.7°C)
- September: 14.3°C (air: 14.0°C)
- October: 11.4°C (air: 10.5°C)
- November: 8.8°C (air: 7.4°C)
- December: 7.7°C (air: 5.5°C)
Nearby Dive Sites in Pacific Northwest
- 100 Foot Rock
- Alki Beach Park
- Alki beach Seattle ferry north
- Am/Pm Beach - 13m (shore)
- Ansell Point Dive Site - 5-20m (shore)
- Arachne Reef - 5-20m (reef)
- Arachne Reef (reef)
- Arbutus Island - 10-30m (shore)
- Arbutus Point - 23m
- Atkins Reef (reef)
- Atrevida Reef (reef)
- Barnard Castle - 15-35m (pinnacle)
- Bell Island
- Blake Island Reef (reef)
- Blind Reef (reef)
Nearest Dive Centres to Obstruction Reef
Marine Life in Pacific Northwest
Home to 38 recorded species including 18 reef fish, 7 crabs & lobsters, 3 whales & dolphins, 2 sharks & rays, 2 clams & mussels, 2 sea urchins.
Notable Species
- Pacific herring (Clupea pallasii) - Reef Fish
- coho salmon (Oncorhynchus kisutch) - Reef Fish
- Spiny Dogfish (Squalus suckleyi) - Sharks & Rays
- Chinook (Oncorhynchus tshawytscha) - Reef Fish
- Dungeness Crab (Metacarcinus magister) - Crabs & Lobsters
- Common shore crab (Carcinus maenas) - Crabs & Lobsters
- red salmon (Oncorhynchus nerka) - Reef Fish
- California Spot Prawn (Pandalus platyceros) - Crabs & Lobsters
- Slender Crab (Metacarcinus gracilis) - Crabs & Lobsters
- Rainbow Trout (Oncorhynchus mykiss) - Reef Fish
- Whiting (Merluccius productus) - Reef Fish
- Pacific krill (Euphausia pacifica) - Crabs & Lobsters
- Common Seal (Phoca vitulina) - Whales & Dolphins
- Eulachon (Thaleichthys pacificus) - Reef Fish
- Red Rock Crab (Cancer productus) - Crabs & Lobsters
- Spotted Ratfish (Hydrolagus colliei)
- Calico salmon (Oncorhynchus keta) - Reef Fish
- Slender Sole (Lyopsetta exilis) - Reef Fish
- Pacific Geoduck (Panopea generosa) - Clams & Mussels
- Olympia oyster (Ostrea lurida) - Clams & Mussels
Recommended Packing List for Obstruction Reef
Based on average water temperature of 11.0°C, currents 7 cm/s.
- Wetsuit (5-7mm) - recommended for 11°C water
- Hood & Gloves (3-5mm) - helps retain warmth
- Mask - essential for every dive
- Fins
- BCD - buoyancy compensator
- Regulator - your most safety-critical piece of gear
- Dive Computer - tracks depth, time, and NDL
- Surface Marker Buoy (SMB) - essential for boat pickups
- Dive Torch - useful for crevices and colour at depth
- Underwater Camera - capture your diving memories