Wildfires 101

Narration: Katie Jepson

Transcript:

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When you think of wildfires,

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you may think of destruction.

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Skeletal forests, property lost and lives forever changed.

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But fires can also bring rejuvenation.

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They can renew ecosystems, nourish the soil, and foster new growth.

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But climate change is causing these fires to burn larger, longer, and more often.

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These larger and more frequent fires damage ecosystems,

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disrupt communities, and can even influence the climate.

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So, understanding the basics of wildfires

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and how they're impacted by climate change,

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is key to our ability to predict where and when fires are likely to occur.

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As well as remotely detect and track wildfires once they ignite,

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and ultimately mitigate their impacts on human health

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and the environment.

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This is Wildfires 101.

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The first thing you should know,

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is that wildfires require three key ingredients:

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fuel to burn, the right conditions, and a source of ignition.

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But what does that actually mean?

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So fuel - like needles, leaves, or wood on the forest floor,

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is rarely a fire's limiting factor.

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And the conditions that are favorable for fire like hot, dry, and windy days,

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are becoming more and more common as our climate changes.

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Under these “fire weather” conditions,

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fuels dry out and become more susceptible to burn.

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As for source of ignition?

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Well, most of the wildfires

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that NASA detects from space are started by people.

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Others, usually in the Arctic and boreal regions, are ignited by lightning strikes.

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NASA can track these conditions and inform land managers

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when an area appears prone to wildfire.

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Every day, NASA is able to detect thousands

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of new fires from space.

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Along with our partners at NOAA,

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we use both polar orbiting and geostationary satellites

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to get insight as to the structure and evolution of a fire.

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Geostationary satellites remain fixed in relationship to the globe,

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giving us new images of one hemisphere every 5 to 15 minutes.

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However, the resolution is usually coarser

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than that of polar orbiting satellites,

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which will pass over a fire twice per day.

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From over 500 miles above Earth,

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these orbiting satellites will detect and characterize thermal anomalies:

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locations on the Earth's surface that are hotter than their neighbors,

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that can indicate burning associated with new

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or existing fire events.

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Importantly, these instruments can detect fires at night -

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a time when wildfires typically lay down and smolder.

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Since the majority of large wildfires lasts for multiple days,

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the ability to track them both day and night is instrumental

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to helping land managers combat the blazes.

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But it's not just the fire itself that's dangerous.

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Wildfire smoke can travel for thousands of miles,

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having the ability to blanket

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large swaths of a continent from a single wildfire.

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Smoke from wildfires can reach high altitudes -

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between 3 to 6 miles - and travel with the prevailing winds.

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This smoke can linger in the air for several weeks,

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changing the chemistry

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of the atmosphere and reducing

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the amount of sunlight reaching the surface.

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Smoke that gets trapped near

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the ground severely impacts air quality in surrounding communities,

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and poor air quality can last for months

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as large fires continue to smolder

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even after the fire itself has been contained.

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Climate change is not only impacting

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the size and intensity of wildfires,

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but also their frequency in some regions.

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NASA has over 22 years of daily fire data to track wildfire trends.

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This is important to get a sense of how fire regimes - the historical

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frequency of wildfires in a region - are changing over time.

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Understanding an ecosystem’s fire regime is important

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because in many instances, wildfire is essential

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to maintain a mixture of younger and older vegetation.

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However, when fires occur too frequently or with increased severity

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it can have devastating effects

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like destroying habitat, changing soil chemistry and clogging waterways.

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Not to mention releasing

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greenhouse gases like CO2 and aerosols into the atmosphere.

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NASA can study wildfire’s impact on the landscape

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by measuring burn scars,

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as well as tracking vegetation loss and rate of regrowth.

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Having an accurate assessment of a landscape post-fire

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is a key part of understanding how ecosystems recover over time.

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NASA’s ability to not only track wildfires,

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but also the conditions that lead to them,

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is essential to our ability to mitigate their impacts.

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We're working with land managers

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and those on the front lines to give them the tools,

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including near real-time data,

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to help them make decisions to minimize the risks

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and plan for the future.