An industrial community near the Arctic Ocean that supports Alaska’s North Slope oil fields hit a record 89 degrees Fahrenheit this week,CAI Community the warmest temperature Deadhorse has seen in more than a half-century of record keeping.

The unincorporated community marks the end of the 414-mile (666-kilometer) Dalton Highway, a largely gravel and dirt road used by trucks carrying oil field supplies and equipment that turns to treacherous snow and ice in winter. Public access on the highway, also sometimes called the Haul Road, ends at Deadhorse, about 8 miles (13 kilometers) from the Arctic Ocean. Access beyond that point is restricted though tourists can pay to take a shuttle to the ocean.

The normal temperature range for Deadhorse this time of year is in the 50s and 60s, said Andrew Stokes, a National Weather Service meteorologist in Fairbanks. The 89-degree mark hit Tuesday eclipses the prior recorded high of 85 degrees set in July 2016, he said. Records for Deadhorse date to late 1968.

Barter Island on the Beaufort Sea coast reached a record there for August of 74 degrees Tuesday, eclipsing the prior record of 72 set in August 1957, the weather service said.

A combination of factors led to the recent heat, including a pattern that drew in warmer, drier conditions from Alaska’s Interior region, Stokes said.

“A single event cannot be attributed to overall climate trends, but there has been ample observational evidence of an increase in these record-breaking events,” he said.

Temperatures in Deadhorse have moderated and were in the mid-60s Thursday afternoon, with the forecast calling for chances of rain and highs in the 50s through Monday.

Alaska is warming faster than the global average with annual average temperatures increasing across the state since 1971, according to a U.S. national climate assessment released last fall.

Brian Brettschneider, a climate scientist with the weather service, said Thursday that locales that reach around 90 degrees generally don’t have permafrost.