Considering how many times Meriwether Lewis, William Clark, and other members of the Corps of Discovery referenced disagreeable weather in their journals, historians could easily assume they experienced a particularly rough winter in terms of rain and cold spells.

To test the that assumption, George Miller, a longtime Pacific Northwest meteorologist, decided to do some research. He shared his findings, which also are part of his 2004 book “Lewis and Clark’s Northwest Journey: ‘Weather Disagreeable,’” during a History and Hops presentation, sponsored by the Seaside Museum and Historical Society, at the Seaside Brewery on March 28.

Especially for first-time visitors, Miller said, the explorers from the expedition deserve “a whole lot of credit for how well they observed the weather.”

Thanks to the Corps of Discovery members’ journals, Miller was able to take their ample references to weather and equate them to weather patterns known to exist in the Pacific Northwest today. Using that information, he created a more accurate picture of what sort of weather the group of explorers experienced during their stay at Fort Clatsop.

For instance, he identified references to as many as three Arctic outbreaks, with severe cold spells; freezing rain the night of Feb. 2, 1806, that lasted into the following morning; and snow depths varying from 4 to 9 inches.

Staying on the Coast

Around November 1805, the group needed to decide where to spend the winter, and their options included The Dalles, moving east of the Cascade Range, and staying at the coast. By choosing the latter, Miller said, “they made the right decision.” As Clark rightly observed, the climate at the coast was milder than that in the mountains. Additionally, they acquired a better understanding of what to expect on the coast.

While the climate they found on the coast was similar in some respects to what they were used to on the East Coast, there were several distinctions, as well — including the constant rain that caused their clothes to rot.

“I counted up how many times they had made the notation ‘weather disagreeable,’ and it was a lot,” Miller.

The journal references made Miller wonder how wet it actually was at Fort Clatsop during the winter of 1805-06, and he began to seek an answer to that question.

Rainy days, past and present

As the company did not have a rain gauge, Miller could not determine how much rain they experienced. However, he was able to calculate how often it rained during the months of their stay and compare it to reported numbers at the Astoria Regional Airport during a more recent year.

In their journals, the expedition reported precipitation on 24 days in November, 31 days in December, 25 days in January, 22 days in February, and 26 days in March, or 128 days overall throughout the winter of 1805-06. Those numbers include four days of snow.

During the winter of 2003-04, rain was reported at the airport on 26 days in November, 29 days in December, 28 days in January, 23 days in February, and 21 days in March, or 127 total — one less than during the Corps of Discovery’s residency.

During the five-month period of November to March, the average precipitation at the Astoria airport is about 46 to 56 inches, Miller said. In 2003-04, with 127 days of rain, the average rainfall from November to March was about 44.96 inches. Miller believes it could have been similar for the Corps of Discovery based on how many days they experienced rain.

“I really don’t consider that a terrible winter in Astoria,” he concluded, adding while the weather was probably average for the area, the explorers were likely unprepared and unused to frequently experiencing rain seven or more days in a row.

Miller did discover, however, there was an unusual cold spell during their stay. Additionally, a series of Pacific storms left a far above average snowpack in the Cascades and Rocky Mountains, as the explorers were unable to cross the Rockies “to go back home until July,” he said.

History and Hops is a series of monthly discussions hosted by the Seaside Museum on the last Thursday of each month from September to May at the Seaside Brewery. The discussions begin at 6 p.m.

On April 25, Fort Clatsop Ranger Sally Freeman will present on several lesser-known women who played an important role in the Corps of Discovery’s expedition.

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