Wednesday, 17 January 2018

Natural Disasters and Family Misfortunes 11: Effects of Natural Disasters on the Unborn

Did any of your ancestors suffer from trauma as a result of a devastating natural event?

Twenty years ago, many parts of Quebec, Canada suffered through an ice storm that knocked out power and paralyzed whole communities. It was also felt in the neighbouring provinces of Ontario, New Brunswick and Nova Scotia, and the US states of New York and Maine. People who were affected still vividly remember the disaster in which 1,000 electrical transmission towers and over 17,000 utility poles were toppled, not to mention the millions of trees lost.
A woman walks past a downed hydro pylon near St-Constant, Que. after one of the worst ice storms to hit Canada struck eastern Ontario and Quebec in January 1998; photo credit: Robert Galbraith/CP photo (downloaded from Global News: Looking back at the Ice Storm of 1998)

Over 3,500,000 people were without power for several days in the coldest part of the winter season. Over 800,000 had to leave their homes to seek relief in community shelters or to stay with family or friends. Thirty-five Canadians died. I won’t go into detail here, but descriptions of the event and how people coped can be found in many articles written just after the event and more recently here: January 1998 North American ice storm; the Great Ice Storm of 1998; Looking back

Freezing rain in the Quebec region is not uncommon. Montreal has such events 12 to 17 times a year with between 45 and 65 total hours of rain. Snow produced at high levels of the atmosphere drop through warmer zones, turn to rain and then spread out over the cold ground, collecting and freezing on every surface. On 4 January 1998, a large low-pressure system stalled over the Great lakes and directed warm, moist air from the Gulf Coast toward the St. Lawrence valley. A coincident high-pressure system was present over Labrador keeping very cold air near the surface of the region. Another strong high-pressure system was anchored over the Atlantic region preventing migration of the two systems to the west from moving. The “perfect” conditions resulted in several inches of rain and consequent large accumulations of ice over 80 hours.

Map showing the accumulation of freezing rain (from Wikipedia: January 1998 North American ice storm

Can there be any doubt that many individuals were traumatized by this brush with a cold death?

Now a generation later, results of studies of people involved – especially those women pregnant at the time or who gave birth during or just after the storm – are being made public. Some of these research projects have reached the national news: 20 years later…, Ice Storm relived

Several Montreal-area researchers at Douglas Mental Health University Institute and McGill University set up a study called Project Ice Stormto study the effects of in utero exposure to varying levels of prenatal maternal stress resulting from an independent stressor on the children’s development from birth through childhood.” Nearly 100 families participated in the project which followed the children through home visits and the use of questionnaires to teachers and parents. The researchers found that the experiences of the mothers affected a whole host of things in their children: IQ, obesity, insulin secretion and their immune system.

The authors report that, “To date, we have obtained significant effects of prenatal maternal stress in every area of development that we have examined. Extrapolating our findings to more severe events, such as war and other forms of natural and man-made disaster, the strong effects we find may possibly be multiplied in other contexts.”

The effects of the 1998 storm left lasting memories on those who lived through it but apparently also on the DNA of children born afterward (see 2014 article, DNA Methylation Signatures Triggered…). Data from the study have shown that “Prenatal maternal stress results in lasting, broad and functionally organized DNA methylation signature in several tissues in offspring. By using a natural disaster model, we can infer that the epigenetic effect found in Project Ice Storm are due to objective levels of hardship experienced by the pregnant woman rather than to her level of sustained distress.” The extent of the maternal stress and impacts on the fetuses was partly dependent on such things as the number of days without power and the damage to the mothers’ homes.

So, I wondered, before the day of scientific, psychological and other such confined studies of specific events, how would we know what effects such major natural disasters might have had on our ancestors in the past. We do have evidence that many surviving families suffered through economic and mental problems following major floods or storms where family members, especially the main bread-winners, were lost.

What genealogists have perhaps not recorded, or have not been able to find, were the personal histories and states of mind of those left behind after fathers, mothers or children were lost. Or, at least, they may not have recognized how lives were changed or mental states developed of those still in the womb. Following the lives of such children might show how or whether people were affected physically or mentally by natural disasters from which their mothers may have been subjected.


Cao-Lei, L., Massart, R., Suderman, M. J., Machnes, Z., Elgbeile, G., Laplante, D. P., Szyf, M. & King, S. (2014). DNA Methylation Signatures Tirggered by Prenatal Maternal Stress Exposure to a Natural Disaster: Project Ice Storm. Published online 19 September 2014 at


  1. This is a fascinating subject. It makes me wonder whether mothers who had grown up in very challenging environments would have similar results in their offspring after an event like that. Would "toughened" mothers pass on the same level of distress to their childen?

    1. I don't know that we know the answer to that yet, or what a "toughened" mother might be. It may be important to keep in mind what tragic events ancestors endured to measure any effects on their offspring.

  2. Hello Wayne, very thought provoking article. Can't imagine what the impact must have been on our ancestors who lost their mother/father/sibling at a young age as the result of a tragedy or epidemic. I'd be interested in knowing the impact emigration to the New World must have had on families, what were their coping strategies?

    1. I agree Penny. It does offer food for thought when one considers the trauma our ancestor no doubt faced with many different types of disasters. I wonder how we will ever know the effects.