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Weather Balloon Instrument/Radiosonde

What to do if you find a weather balloon/radiosonde:


Image of Vaisala RS92 RadiosondeImage of Lockheed martin Mark IIA MicrosondeImage of LMS6 Radiosonde

Vaisala RS92 RadiosondeLockheed Martin Mark IIA MicrosondeLMS6 Radiosonde

(Click on the captions above to see a larger view of the photo)

If you have found a National Weather Service (NWS) Radiosonde, it is safe to handle. Photos of NWS radiosondes are shown above.

If the NWS radiosonde is not seriously damaged (styrofoam or plastic packaging is not broken apart) and was not found floating in water or at the shoreline, it can be sent back to the NWS where it will likely be refurbished and flown again, lowering the cost of the weather balloon program. If the radiosonde is damaged or was exposed to water, please discard it in the trash. Follow these instructions for mailing the radiosonde to the NWS:

(1) Cut and discard the string to the burst balloon and orange parachute. IMPORTANT: On rare occasions the balloon may be found partially inflated with gas. The gas inside the balloon may be flammable hydrogen. If the balloon is inflated, stay away from it and contact your local fire department for safe disposal.

(2) If you find a Mark IIA Microsonde (see photo above), remove and discard the battery inside the radiosonde. NOTE: The battery (generating less than 12 volts) is water soaked and uses a chemical containing sulfur. If the battery is still active when you find the radiosonde it may be hot to the touch and emit a strong odor and hissing sound for up to several more hours. Keep the instrument outside and wait until the battery has cooled off before removing it.

(3) Remove the plastic mailbag enclosed in the radiosonde and place the instrument inside the bag. If the mailbag is missing, please send an email with your mailing address to and a mailbag will be sent to you.

(4) Hand the radiosonde package to your mail carrier. Do not leave the package unattended at a post office mailbox or elsewhere. Postage is prepaid if the instrument is mailed in the United States. If the instrument is found in Canada or Mexico, postage is not prepaid and the instrument should be discarded in the trash. More information on radiosondes can be found here:

Fact Sheet

If you have any questions on radiosondes, please send an email to:

National Weather Service
Office of Operational Systems (OPS2)
1325 East-West Highway
Silver Spring, MD 20910
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Last Modified: November 3, 2009
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