Weather Almanac for May 2004

NEW ENGLAND'S DARK DAY

The abnormal darkening of daytime skies has often held fear and dread for humans and confusion among animals. There can be several causes for unexpected dark days: severe thunderstorms, solar eclipses, volcanic dust clouds and wildfire smoke and ash. Today, we are able to predict the exact moment of solar eclipses, and observation and communication networks keep us abreast of any severe storms, volcanic eruptions and wildfires. In 1780, however, this was not the case; information moved no faster than Paul Revere's ride. In May of that year, during a crucial time in the American Revolution, the skies over New England darkened, and no one knew why.

Though daytime skies for several days had been unusually coloured — a dirty yellow tinge with a reddish-hued sun — no one in New England was fully prepared for the darkness that descended over the region on the morning of 19 May. When an early descending darkness took hold around the noon hour, all life reacted. Birds began singing their evening songs, then went silent and disappeared from view; frogs began to peep. Chickens returned to their roosts, and cattle walked slowly back to their barns, thinking evening had descended. Human outdoor travel became difficult. Professor Daggett of New Haven, Connecticut reported: "The greatest darkness at least equal to what was commonly called candle-lighting in the evening. The appearance was indeed uncommon, and the cause unknown."

Opinions as to the cause of the darkness were mixed. Yale president Timothy Dwight observed: "It was the general opinion that the day of judgment was at hand." Many New Englanders abandoned their daily activities and congregated at hastily-convened religious services. Those with a more scientific viewpoint examined the sky and rain water that fell during the event to find a cause. In any case, the day would go down in history as "New England's Dark Day," "Black Friday" and even "The Wonderful Dark Day."

The Prelude

From the many diaries available from the period, David Ludlum was able to reconstruct a general synoptic picture of the event and surrounding days over the American Northeast ("New England's Dark Day: 19 May 1780" Weatherwise, June 1972). The following summarizes his research.

For most of the preceding days of May, New England had been under the influence of cool temperatures and clear skies, indications of an anticyclonic influence with Canadian origins. Barometric records from Cambridge show high and steady pressure. In Salem, Massachusetts (records of Dr Edward Holyoke), the last rainfall had been observed on the 8th. Easterly winds on the 17th and 18th, indicate the high center now sat to the east. Several diaries reported a smoky aspect to the sky and a red hue to the sun for several hours after sunrise and before sunset.

The morning of the 19th dawned cloudy and cool at Salem, early morning temperature at 43^oF (6.1^oF). The barometer was falling and continued to do so until after 10 AM at Bradford MA. A southwest wind was blowing, indicating that eastern Massachusetts was in the warm sector of a low pressure-trough frontal system. Across portions of eastern New England, showers and thundershowers fell before noon. Clouds would prevail across the region for much of the day, giving a darkness to the day in general, but how much was water cloud and how much was something else — likely smoke particles as we shall see — we cannot fully determine.

The Event

As the extraordinary darkness descended, those observing it wondered if it was a local phenomenon or more widespread. With no rapid communication networks in place, the only way to determine the extent of the darkening was through letters and newspapers from across the region. After the event, Professor Samuel Williams of Harvard College undertook the collection of such information from across the region. He was able to determine that notice of the darkness was taken as far south as northern New Jersey and New York City coastal waters, as far north as Portland, Maine and west into the Hudson Valley, but no mention came from Philadelphia or outlying Pennsylvania. (The New Jersey report came from George Washington's diary at Morristown.) Williams concluded the dark centre of the event was located around northeastern Massachusetts, southern New Hampshire and southwestern Maine.

Site Map for New England Communities Mentioned in Text

At Rupert, New York along the Vermont border, the sun rose greatly obscured and remained so until late morning. At the eastern extreme, at Barnstable MA on Cape Cod, the event began around 2 PM with peak obscurity around 5:30 PM. Thus, calculated Ludlum, the obscuring "cloud" took about seven and a half hours to move from Rupert to Barnstable, a distance of 180 miles (289 km) and thus advanced with a speed of 25 mph (40 km/h).

At Harvard College, student Nathan Read recorded frequent observations of the darkness. His first remark that something was extraordinary came at 10:30 AM: "An uncommon degree of darkness comminied [commenced?] while increased pretty rapidly." At 11 AM, he noted: "Mr Wigglesworth not able to read in a large bible by a window." At 12:21 PM, he added: "Mr W. not able to read the running title of a large Bible. — Candles are in common use..."

For Read, the darkness peaked at 12:45 PM: "...not able to read to determine the time of day, by a china faced watch, in S.W. room having three windows." Shortly thereafter, the darkness abated from its depth so that by 1:10 PM, he commented: "Cocks have continued to crow as at day breaking." But the afternoon continued dark, "the same as common in a thick cloudy day."

The intensity of the darkness was described by many observers:

"In some places, the darkness was so great, that persons could not see to read common print in the open air.... The extent of this darkness was very remarkable." Prof. Samuel Williams, Cambridge MA.

"The darkness of the following evening was probably as gross as ever has been observed since the Almighty fiat gave birth to light.... A sheet of white paper held within a few inches of the eyes was equally invisible with the blackest velvet." Dr Samuel Tenney of Rowley, (MA?), letter dated from Exeter (NH?).

"By 12, I could not read anywhere in the house — we were forced to dine by candle light. It was awful and surprising." Rev. Ebenezer Parkham, Westborough, MA.

Artist's Rendition of Dark Day of 1780
from Our First Century by Richard M. Devens (1880)

Prof. Daggett remarked the low-level clouds took "a strange yellowish and sometimes reddish appearance...an unusual yellowness in the atmosphere made clean silver nearly resemble the colour of brass." Nathan Read saw "a uniform cloud appeared of a cast compounded of a faint red, yellow & Brown." Others remarked on the hue thrown on grass and foliage. "An uncommonly lovely verdure, a deepest green, verging on blue," observed Williams. Dr Samuel Tenney viewed "so enchanting a verdure as could not escape notice, even amidst the unusual gloom that surrounded the spectator."

Our biggest clue as to the cause of the darkness comes from the observations of Williams of the nature of the rain that had fallen on Cambridge. "The water...was found to have an uncommon appearance, being thick and dark and sooty...I examined a quantity of this matter; and in taste, colour and smell, it very plainly appeared to be nothing more than what the gentleman observed at Ipswich, — the black ash of burnt leaves, without any sulphureous, or other mixtures." In Ipswich MA, rainwater collected in tubs was covered by a black scum like ashes and gave a strong sooty smell, according to Reverend John Lathrop. Jeremy Belknap of Boston noted the air smelled like a "malt-house or coal-kiln" during the darkness.

Impacts

Regardless of the true cause, the event brought concern to many, fearing the anger of God or demons. At Salem, it was reported "persons in the streets became melancholy and fear seized all. Prof. Daggett remarked "the inhabitants were thrown into a perhaps unnecessary consternation, as if the appearance were preternatural." In Stratham, New Hampshire, the darkness "caused great terror in the minds of abundance of people." In Ipswich Rev. Lathrop "found the people at the tavern nearby much agitated."

The most interesting reaction came from the Connecticut Legislature sitting at Harford. The general opinion of many legislators was that the day of judgment was at hand. In the House of Representatives, members being unable to transact their business adjourned, according to Timothy Dwight. A move to adjourn the Council was opposed by Colonel Abraham Davenport who purportedly rose in opposition. "I am against an adjournment. The day of judgment is either approaching, or it is not. If it is not, there is no cause of an adjournment: if it is, I choose to be found doing my duty. I move that candles be brought, and we proceed to business." (Davenport has been immortalized for this stand in a poem "Abraham Davenport" by John Greenleaf Whittier.)

A Likely Cause

Professor Williams reasoned that the cause of the darkness was due to an atmosphere highly charged with "vapours" which refracted, reflected, absorbed, and thus greatly weakened the incoming sunlight. He was close. The most plausible cause for those "vapours" was wildfire ash and particles based on both his and Lathrop's observations of the rainwater. The particulate burden likely came from forest fires burning in the wilderness to the north that was drawn into the synoptic circulation. (A poem, thought to have been written in 1780 but not published until 1833, suggested burning woods in New Hampshire "sent smoke up dense and smothering.")

There are local antecedents for such a source of particles affecting daylight. In September 1881, smoke from forest fires in Ontario and Michigan blanketed the Northeast with an eerie haze that reduced sunlight dramatically — though not as great as the Dark Day of 1780. Estimates at Harvard put the sunlight received that day at one tenth the level of an average cloudy day. Another event, "The Great Smoke Pall" of 1950 emanating from western Canada forest fires covered the region with a dense smoke cloud. And most recently during July 2002, dozens of forest fires raging across northern Quebec sent a thick smoky haze southward as far as Washington, DC. The smoke cloud prompted health advisories in Quebec, New York, New Jersey and Pennsylvania.

Addendum

The memories of the Dark Day continued for many years in tale and legend. I recently heard from a reader (Judy Anne) who informed me that a famous quilt sown by former slave Harriet Powers (1847-1910) included a panel depicting the Dark Day event. Powers was not yet born when the event occurred, but it obviously was recounted by those she knew. The quilt is considered to be one of the most significant quilts in the world and resides in the Boston (MA) Museum of Fine Arts.

Written by
Keith C. Heidorn, PhD, THE WEATHER DOCTOR,
May 1, 2004, revised November 2006

The Weather Doctor's Weather Almanac New England's Dark Day
©2004, 2006 Keith C. Heidorn, PhD. All Rights Reserved.
Correspondence may be sent via email to: see@islandnet.com.

For More Weather Doctor articles, go to our Site Map.

I have recently added many of my lifetime collection of photographs and art works to an on-line shop where you can purchase notecards, posters, and greeting cards, etc. of my best images.

To Purchase Notecard, Greeting Cards and Posters featuring my images, visit The Weather Doctor's Nature Gallery

Now Available! Order Today!
NEW! Now Available in the US! And Now...The Weather by Keith C. Heidorn To Order in Canada: And Now...The Weather by Keith C. Heidorn	The BC Weather Book: From the Sunshine Coast to Storm Mountain by Keith C. Heidorn