When It Rains, It Pours: New Study Finds Extreme Snowstorms And Deluges Are Becoming More Frequent And More Severe

As our climate warms, wet areas will generally get wetter (and dry areas drier). One of the consequences of global warming is the severity and frequency of rain and snow storms – fueled by the increase moisture in the atmosphere as the air warms.

A new report released by Environment America Research & Policy Center analyzed more than 80 million daily precipitation records across the United States from 1948 through 2011. The analysis reveals that climate change is now affecting the large rain or snowstorms.

The following are highlights from the report:

  • Extreme downpours – rainstorms and snow falls … are now happening 30 percent more often on average across the contiguous United States than in 1948.
  • New England has experienced the greatest change with intense rainstorms now happening 85 percent more often than in 1948.
  • Not only are extreme downpours more frequent, but they are more intense. The total amount of precipitation produced by the largest storm in each year at each station increase by 10 percent over the period of analysis, on average across the contiguous United States.

Just like a baseball player on steroids hitting more homeruns, climate change is weather on steroids and industrial pollution if fueling the extreme weather. Though we are experiencing droughts due to the U.S. southwest and southeast drying out, precipitation is increasingly concentrated into heavy downpours space further apart.

The fingerprint of climate change can be clearly identified with the increase and severity of rain and snowstorms.

The report explains that due to humans increasing emissions of heat-trapping gasses in the atmosphere – including pollution from fossil fuels – warmer temperatures in the atmosphere cause more evaporation. With warm air sitting in the atmosphere holding more water, when it rain – it pours ultimately intensifying the water cycle.

Another finding in the report is that 43 states showed statistical “significant” increase in the frequency of extreme storms. The authors define “significant” as a high probability the trend is real based on statistical analysis. The map below identifies the regions of the U.S. and recognizes the increase in frequency of rain and snowstorms:

According to the World Metrological Organization’s provisional status report issued at the United Nations climate talks in Durban, 2011 was the 10th warmest year on record and warming than any over year with a La Nina event.

But the United States is not the only country to experience extreme rain, snow, and flooding. Australia saw the country’s worst floods since 1974. A surge of rain in Brazil caused deadly landslides north of Rio de Janerio. Rainfall during June to September’s monsoons season in Thailand was up to 80% higher than the season average according to the WMO.

It is becoming much clearer how climate change affects extreme weather.

— Matt Kasper

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16 Responses to When It Rains, It Pours: New Study Finds Extreme Snowstorms And Deluges Are Becoming More Frequent And More Severe

  1. prokaryotes says:

    The Clausius-Clapeyron relation shows how the water-holding capacity of the atmosphere increases by about 8% per Celsius increase in temperature.

  2. prokaryotes says:

    This basically means that with the best scenario we have (MIT policy scenario 2009), which projects 3-4C temperature rise, we will experience 5 times more extreme precipitation events than currently. Which probably means catastrophic structural damage in affected areas. More and more it appears that the erosion and geomorphological response – high impact gravitational mass redistribution will be much more pronounced and severe.

  3. prokaryotes says:

    Evidence for Rainfall-Triggered Earthquake Activity

    Fluids are known to be of major importance for the earthquake genera- tion because pore pressure variations alter the strength of faults. Thus they can initiate earthquakes if the crust is close enough to its critical state. Based on the observations of the isolated seismicity below the densely monitored Mt. Hochstaufen, SE Germany, we are now able to demonstrate that the crust can be so close-to-failure that even tiny pressure variations associated with precipitation can trigger earthquakes in a few kilometer depth.

  4. prokaryotes says:

    The fast response of volcano-seismic activity to intense precipitation: Triggering of primary volcanic activity by rainfall

    One-minute resolution time series of rainfall and seismic data from the Soufrière Hills Volcano, Montserrat are analysed to explore the mechanism of external forcing of volcanic eruptions by rainfall over three years of activity. The real-time seismic amplitude (RSAM) shows a narrow, statistically significant, peak within 30 min after the start of intense rainfall events, and a much broader peak with a lag of 6–40 h. The classified seismic events indicate that the volcanic response to rainfall begins at the surface and gradually penetrates deeper into the dome, as there is an increase in the pseudo-magnitude of: surface rockfall events (including pyroclastic flows) with lags from the first 30 min to 40 h, long-period rockfalls (from shallow degassing) at lags of 4 and 14 h, and long-period and hybrid events (source depth approximately 1 km) with lags at 14 and 24 h after the start of rainfall events.

  5. A similar analysis for California shows a wide discrepancy between N of San Francisco Bay and land to the South. Most of the extreme weather will be in Southern California.

    A new report suggests that global warming is playing out quite differently in California, depending on whether it’s north or south of San Francisco Bay.

    The project, by the Environment California Research & Policy Center, studied precipitation trends between 1948 and 2011, with an eye on “extreme” events — storms that dumped unusual amounts of rain or snow on the state.

  6. Anne says:

    Don’t need no dern study to know dat! In DC, we go from drought to deluge, back to drought. Gone are the days of those slow, meandering, lazy rains that would gently soak the earth. It feels like the skies are angry and acting out.

  7. Leif says:

    It is all about energy in my view. With the added energy of one million Hiroshima size bombs each day added to the commons, how could it be otherwise. (~1 bomb/16 mile diameter circle on earth!) Still growing and the NEW NORMAL! Extra energy to evaporate moisture and power storms. Alter jet streams, and melt the polar ice caps and glaciers. Intensify heat waves.

  8. Rob says:

    Global warming doesn’t mean it will never snow. But it does mean there will be more extreme snowstorms. Any time there’s a big snowstorm, someone scoffs, “Global warming?! Yeah, right!” There are a few problems with that. First: It confuses a short-term, local event with the long-term trend that the planet is getting warmer. But here’s another fact that might surprise you. Even though the total amount of snow has declined in parts of the world over recent decades, there have been an increasing number of very heavy storms. That’s because a warmer climate increases evaporation, drawing moisture both from the oceans and the land. When that increased atmospheric moisture feeds into a storm, it can make the storm really, really big. The result: less snow overall as temperatures increase, but more extreme snowstorms.

  9. Jamie Ross says:

    and one more thing – Record snow is not really a counterargument to global warming. Record cold is. They are not the same thing and they don’t necessarily go together.

  10. Paul Klinkman says:

    Actually, record cold isn’t a counterargument to climate change. More powerful storms fueled by all that moisture are likely to pull colder air down from polar regions.

    New England is experiencing a new phenomenon that I don’t remember seeing as a long-time resident. We’re getting snow before frost in the fall. The falling snow drops our local surface temperature down to 32 degrees F. but not to 31 degrees F, which would freeze out the plants. We had a really horrid example last Halloween when up to 15 inches fell on some places with green leaves still on the trees. The snow stuck to the tree leaves, bringing down plenty of trees and blacking out almost everyone’s electric power in the region. We had no frost.

  11. Paul Klinkman says:

    Whenever supersaturated marine air blowing northward from the tropical Atlantic rides up over the cold New England land, rain or snow breaks out. Afterwards a low pressure system forms right on top of Nantucket, pulling more precipitation out of the sky.

    Rhode Island had 8 inches of rain during one March storm a year ago. Route 95 was shut down for a few days because a river covered it. The real danger in New England is getting the same storm in February, when the region would instead get 8 feet of new snow on top of what snow we already had. Most house and building roofs would collapse. Those houses with electricity would soon run out of fuel oil.

    And you thought drought was the problem.

  12. prokaryotes says:

    IPCC – How is Precipitation Changing?

    As climate changes, several direct influences alter precipitation amount, intensity, frequency and type. Warming accelerates land surface drying and increases the potential incidence and severity of droughts, which has been observed in many places worldwide (Figure 1). However, a well-established physical law (the Clausius-Clapeyron relation) determines that the water-holding capacity of the atmosphere increases by about 7% for every 1°C rise in temperature.

    Observations of trends in relative humidity are uncertain but suggest that it has remained about the same overall, from the surface throughout the troposphere, and hence increased temperatures will have resulted in increased water vapour. Over the 20th century, based on changes in sea surface temperatures, it is estimated that atmospheric water vapour increased by about 5% in the atmosphere over the oceans. Because precipitation comes mainly from weather systems that feed on the water vapour stored in the atmosphere, this has generally increased precipitation intensity and the risk of heavy rain and snow events.

    Basic theory, climate model simulations and empirical evidence all confirm that warmer climates, owing to increased water vapour, lead to more intense precipitation events even when the total annual precipitation is reduced slightly, and with prospects for even stronger events when the overall precipitation amounts increase.

    The warmer climate therefore increases risks of both drought − where it is not raining − and floods − where it is − but at different times and/or places. For instance, the summer of 2002 in Europe brought widespread floods but was followed a year later in 2003 by record-breaking heat waves and drought. The distribution and timing of floods and droughts is most profoundly affected by the cycle of El Niño events, particularly in the tropics and over much of the mid-latitudes of Pacific-rim countries.

  13. Spike says:

    A quote from the report that is of interest:

    In recent years, scientists at institutions in Australia, the United States, the United
    Kingdom and Canada published evidence suggesting that the models of future
    climate change are underestimating the magnitude of future increases in precipitation intensity.

    Dr. Seung-Ki Min at Environment Canada and colleagues found that “changes in extreme precipitation projected by models, and thus the impacts of future changes in extreme precipitation, may be underestimated because models seem to underestimate the observed increase in heavy precipitation with warming” that has happened over the past half century.

  14. Chris Colose says:

    Here’s is a slightly technical article on the water vapor feedback which some people may find of interest

  15. John Paily says:

    Earth is in critical state, but the situation can change provided we understand the simple energy cycle in which we live and develop energy management of earth’s environment and its core and develop new technologies that release less heat into the
    environment – life gives ample clue to head in this direction
    read article “Critical thinking on global warming and increased Natural Catastrophes ” –

  16. John Paily says:

    This was a predictbale reality from commonsense. Yet the world has failed to take
    note. We have reached now or never situation.
    The situation can change and a golden age can set in provided we understand the simple energy cycle in which we live and develop energy management of earth’s environment and its core and develop new technologies that release less heat into the
    environment – life gives ample clue to head in this direction
    read article “Critical thinking on global warming and increased Natural Catastrophes ” –