A dead gray whale has floated underneath a busy commuter ferry terminal in downtown Seattle, sending a putrid odor wafting onto the dock and diverting some passenger ferries to another slip, a transportation official said on Thursday.

Scientists from the National Oceanic and Atmospheric Administration planned to remove the carcass later in the day and perform tests to determine the cause of death, said Susan Harris, a spokeswoman with Washington State Ferries.

The whale carcass, which Harris described as "a little bit smelly," was estimated at between 25 and 35 feet (7.6 and 10.6 meters) long and had apparently drifted in from open waters, lodging under the busy Colman Dock in Seattle.

There has been no impact on ferry service, used by thousands of commuters each day to reach jobs in Seattle, though only two of the three slips at Colman Dock were operating until the whale could be removed, transportation officials said.

Some ferries to and from upscale Bainbridge Island were diverted to a different slip after the whale was discovered late on Wednesday, officials said.

The gray whale gets its name from its mottled gray skin, according to local whale research group, the Orca Network.

The whales live in the Pacific Ocean, traveling from Baja to the Pacific Northwest, and generally arrive in the Washington state area in late winter or early spring, the group said.