CS705 Snowfall Adapter for Rain Gages with 8 in. Orifices
Uses No Power
Melts snow without heater
weather applications water applications energy applications gas flux and turbulence applications infrastructure applications soil applications


The CS705 is a snowfall adapter that converts a standard 8 in. tipping bucket rain gage to a year-round rain and snow gage. It is typically used with our TE525WS rain gages.

The CS705 consists of the following:

  • One black catch tube
  • One reservoir
  • One overflow (measurement) tube
  • One 14807 drain funnel
  • Two stainless-steel band clamps
  • One set of CM270 mounting hardware

Solid precipitation is gathered in the catch tube and mixed with a non-toxic propylene glycol and ethanol (PGE) solution inside the reservoir. The PGE solution lowers the melting point of the frozen snow and allows the resulting liquid solution to flow through the overflow tube and be measured with a standard 8 in. rain gage.

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Benefits and Features

  • Melts snow without a heater and therefore eliminates the current consumption associated with heaters
  • Converts a TE525WS to a rain and snow gage
  • Collects PGE/precipitation mixture below the rain gage for disposal according to local requirements


Exploded view of the CS705 showing all of its components
CS705 with TE525WS precipitation gage and mounting pole (sold separately)
CS705 with TE525WS precipitation gage (sold separately)
CS705 with TE525WS precipitation gage, mounted to tripod (sold separately)
CS705 with TE525WS precipitation gage and mounting pole (sold separately)
Exploded view of mounting kit
Exploded view of CS705 with TE525WS precipitation gage (sold separately)

Detailed Description

The CS705 consists of a propylene glycol and ethanol (PGE) reservoir, overflow tube, and catch tube. Snow captured in the catch tube dissolves into the antifreeze. The melted snow raises the level of the antifreeze and water solution. The mixture flows through the overflow tube into the tipping bucket where it is measured by the tipping bucket mechanism.

Measurement Delays

The CS705 possesses inherent delays and is not suitable for real-time precipitation measurements. The following factors contribute to the delays:

  • Temperatures of air and liquid in the reservoir
  • Surface tension in the overflow tube
  • Form of the precipitation

For rainfall at 25°C, a delay of minutes is expected after the gage receives a minimum accumulation of ~0.03 inches. For snowfall, a delay of hours to tens of hours is expected. The longest delays should be expected for low-density snows at very cold air temperatures. However, all precipitation falling into the catch tube eventually flows through the overflow tube and is measured by the tipping bucket rain gage.

Recommended Mixture

The CS705 requires a specific 1:1 formulation of propylene glycol and ethanol (PGE) to function properly. PGE is available from Campbell Scientific in a package of four, one-gallon containers (see Ordering Information). Due to regulatory restrictions, PGE can only be shipped in multiples of four gallons via UPS Ground and cannot be shipped outside of the continental US.

Why Straight Car or RV Antifreeze is NOT Recommended

Standard RV antifreeze consist of propylene glycol or ethylene glycol, which has a specific gravity of greater than 1. This allows a layer of water to sit on top of the antifreeze. That layer of water can then freeze and form an ice cap that prevents snowfall from being dissolved in the solution. Cutting the antifreeze with ethanol solves the specific gravity issue and prevents the ice cap. PGE is also more environmentally friendly.

Disposing of PGE Mixture

Although PGE is non-toxic, the PGE/precipitation mixture from the tipping bucket gage should be captured and disposed of properly in accordance with local, state, and federal regulations.


Compatible Antifreeze Mixture 1:1 mixture of propylene glycol and ethanol (PGE)

Campbell Scientific does not recommend using the antifreeze that is typically used in cars or RVs; refer to the Compatibility section for more information.
Material Powder-coated aluminum
Capacity 20.3 cm (8 in.) of liquid @ -20°C (assuming 1:0 starting ratio of antifreeze to water)
PGE Reservoir Capacity 9.46 L (2.5 gal)
PGE Reservoir Diameter 20.96 cm (8.25 in.)
PGE Reservoir Height 35.6 cm (14 in.)
Catch Tube Orifice 20.3 cm (8 in.)
Catch Tube Height 25.4 cm (10 in.)
  • 2 kg (4.4 lb) without PGE
  • ~9 kg (20 lb) with PGE


Tipping Bucket Rain Gages

The CS705’s specially shaped cylinder allows it to mount to the 8-in. orifice of the TE525WS Tipping Bucket Rain Gage. The CS705 cannot be directly used with the TE525, TE525MM, CS700, TB4, or TB4MM tipping bucket rain gages. Both the TE525 and TE525MM can be converted to a TE525WS by returning them to Campbell Scientific.


The CM270 Mounting Kit is included with each purchase of the CS705 Snowfall Adapter. The kit consists of a funnel, two band clamps, and mounting hardware. The funnel drains the antifreeze/precipitation mixture into a pail. One of the band clamps secures the top of the CS705 to a pole. The other band clamp attaches the funnel and the bottom of the rain gage to the pole.

A user-supplied pole or a CM300-series mounting pole may be used. The user must provide a pail and a hose with a 0.5 in. inner diameter. The hose must be long enough to span the distance from the funnel outlet to the pail.

Frequently Asked Questions

Number of FAQs related to CS705: 5

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  1. Yes. In the Quickstart section of the instruction manual, Figure 4-1 and Figure 4-2 provide labeled images of the parts with their corresponding part numbers.

  2. The CS705 works with the TE525WS-L rain gage.

  3. Yes. Mixed rain and snow does not cause any issues for the CS705.

  4. Generally, the antifreeze is changed after 8 inches of liquid water have been added to the antifreeze/ethanol mixture.  Eight inches of water will dilute the antifreeze/ethanol mixture to the point where freezing will occur at -20 degrees Celsius.

  5. The CS705 Tipping Bucket Snowfall Adapter cannot be used directly with the TE525-L or TE525MM-L because of the funnel size. To make the rain gages compatible, they can either be sent to Campbell Scientific to be converted to a TE525WS-L, or an 8 inch funnel can be installed. If the funnel is used, see the instruction manual for the appropriate multipliers, as they will change.

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