In April 1815, Mt. Tambora, a volcano on an Indonesian island, first stirred and then exploded. Of the 12,000 inhabitants of the island, only 26 survived. 4,000 feet of the volcano was blown off, the ensuing eruption ejected an estimated 25 cubic miles of debris. As in many large eruptions, dust and sulphate aerosols were injected into the stratosphere and took months to gradually settle back to the troposphere where weather systems could wash them back to the ground.

The eruption was the biggest of perhaps the last 10,000 years, dwarfing Krakatoa (1883, 4.5 miles³) and Mt. St. Helens (1980, 1 mile³). The stratospheric cloud stretched around the Earth, spread north throughout the northern hemisphere, and reflected enough sunlight to affect weather patterns. In some parts of the world, the impact was minor but in much of Europe it caused near famine conditions. In New England it helped changed history.

In 1816, family farms were largely subsistence affairs. Transporting crops to the cities was feasible only along waterways. The major crop was Indian corn, most which was fed to livestock during the long winters, but it was a staple for human consumption too. Wheat was prone to a fungus, apples and potatoes did well. (Johnny Appleseed was in the middle of his career, planting apple trees throughout the new states around Lakes Erie and Michigan.)

Several cold spells in May 1816 delayed the start of the planting season. June began well, but crops were lost in a cold spell between the 5th and 11th. Snow accumulated throughout all but southernmost New Hampshire. A warm spell starting the last third of June provided hope that summer had arrived, but a killing frost on July 9th dashed that hope. The rest of the month was warmer, but didn't equal the warmest days of June. A warming trend in August abruptly ended with frost on the 21st and a worse one on the 30th.

Some crops did well, apple and pear harvests were very good, perhaps due in part to the cold weather being hard on insect pests. Potatoes did well too. Some people were able to raise a good crop of wheat, and they were rewarded with prices that were double that of normal years. Increased farm efficiencies have exceeded inflation - the high price was never equaled until the 1970s.

In Ashland, Reuben Whitten shared his wheat crop with his neighbors. After his death in 1847, they paid for his headstone in his family graveyard. Later, relatives erected a monument saying "A pioneer of this town. Cold season of 1816 raised 40 bushils of wheat on this land whitch kept his family and neighbours from starveation." His farm was on a south facing hillside, so probably benefited from the extra sun and being above the valley chill.

After 1816, the weather returned to normal conditions quickly. However, farmers had already started emigrating to the more hospitable weather and soil of Ohio and further west. This migration helped accelerate the construction of the Erie Canal, which started construction in 1817 and was completed in 1825. Others went to the mills in Manchester and Lowell, others went to the seaports of Nantucket and New Bedford to learn the whaling trade. Another impetus to the westward migration was an energy crisis - much of the accessible first growth forest had been cut for construction, fuel, and products. Today's New Hampshire is much more forested than it was in 1816.

The westward emigration decimated the population of many farming communities in New Hampshire. To this day, many northern towns have a smaller population than they had in 1816, many more exceeded the old population only when NH began a long growth phase after 1960. Ashland was part of Holderness until 1868. They, and neighboring Plymouth, have rivers with waterfalls, so their economy could shift to manufacturing. In fact, Holderness was in the midst of a growth boom. In 1820 its population climbed to 1160 after growing of 57% and then 40% in the previous decades.

Plymouth's northwest neighbor, Rumney, is a better example. While it grew 22% and 13% to 864 in 1820, it declined to 820 by 1960! (In 2000, population reached 1480, with most of the growth between 1970 and 1990.)

Much of this WWW page comes from Henry and Elizabeth Stommel's book Volcano Weather. It was published the year after the El Chichon eruption in 1982 which brought an end to azure skies for a couple years. That eruption let scientists discover that the sulphuric acid aerosol in the Stratosphere was more important than dust in terms of longevity and sunlight reflecting. The book has a good summary of the research and computer models of the day and graphs that show the beginning of the recent apparent climb in world temperatures.

An easier reference to find is their article in the June 1979 Scientific American which formed the basis for the book.

The Stommels' accounts are the most complete, at least as far as the effects in New England. Of course, anyone who knows anything about New England weather would expect that David Ludlum's writings would be the primary reference - the Stommels' essentially stand on his shoulders. They also refer to some books by J.D. Post written in the 1970s that look at the economic crisis due to the food shortages in 1816. Many oceanographers have stood on Henry Stommel's shoulders.

Many libraries have Scientific American on microfiche. Volcano Weather is available at the Concord NH Public Library, the Lamson Library at the Plymouth NH State College and the Metro Boston Library Network.

Personal note: I read about the Ashland monument when the Scientific American article came out. At the time, my parents had a second home in Plymouth, next door to Ashland. I've always wanted to see the monument in place, but never pursued it until the activity "Geocaching" was invented and I became active. It occurred to me that the monument could be an ideal geocache site as it is significant, but not enough to warrant commercial or state development. With assistance of the WWW, I gleaned it was in a cemetery near Highland Street, and I was able to find it on my own on 2002 May 17. The next day while I was cooking breakfast in a lodge in Woodstock, I watched rain change to snow. While I've seen other memorable snow storms in May, it felt very, very weird to be seeing 1816 weather the day after visiting the 1816 monument!

If you want to visit the monument yourself, details are on the Summerless Geocache page. The cemetery is surrounded by private property, so tread with respect.

Over Christmas in 2005, the National Geographic cable channel's Naked Science program ran a program on what might happen if there were another supervolcano eruption. While the program itself was not very good, it referred to events in Yellowstone in 2003, the last time I visited there, and the effects the eruption could have on weather. That referred to 1816, and they have a scene with a geologist visiting the Whitten monument.

For the 200th anniversity in 2016, I wrote A Tale of Two Freezes, a detailed look at the weather in NH between April and September. Read it some day when you have the time.

While I was researching before writing this page, I came across a new theory that adds another possibility to "abrupt climate change." Decreasing salinity in the North Atlantic seas around Greenland may override the Gulf Stream, cutting off a major heat source for Europe. This can happen in just a few years and there is evidence for such sudden changes in Greenland ice cores. I delve into this a bit more and offer links to better pages at 2016: The [Next] Year without a Summer. It's an interesting theory and deserves to be more widely known. Now that it's featured in this year's summer disaster movie, well, let's just say it deserves to be better understood.

Later on I realized that 1816 was part of the Dalton Minimum, a period of reduced solar activity. Such periods tend to be cooler than usual and the years leading up to 1816 were cold and difficult. Napoleon's invasion of Russia in 1812 suffered dreadful losses, many of them due to the early and harsh winter during the return from Moscow.

We may be entering a similar period of solar inactivity. Solar Cycle 24 was expected to begin in 2006, it may not start until 2009. Long lived cycles and low sunspots numbers are key signs of reduced activity. We have just begun to learn enough about the sun to make predictions, and something similar to the Dalton Minimum is common theme.

Should that happen, then the scenario in 2016 won't play out. On the other hand, we might revisit the weather that destroyed Napoleon's army. See Science, Method, Climatology, and Forgetting the Basics for more about what this means to climatology.

Contact Ric Werme or return to his home page.

Last updated 2016 June 7.