No rain, and no rain gauge

A very long spell with no rain

My town, Manilla NSW, may be having one of the longest periods without rain in 133 years. We will never know.

The records of the Manilla Post Office rain gauge, No. 055031, show that the longest periods without rain were as follows:
1. August 1946: 62 days;
2. April 1912: 55 days;
3. Apr-May 2002: 47 days;
4. August 1914: 46 days;
5. May 1927: 45 days;
6. Mar-Apr 1980: 44 days;
7. April 1925: 43 days;
8. August 1982: 42 days;
9=. March 1896: 41 days;
9=. August 1995: 41 days;
11. March 1934: 40 days;
12. April 1942: 38 days;
13. March 1981: 37 days;
14. March 1955: 36 days.
To judge by my rain gauge, we have had a rainless period that is already equal seventh longest since 1883. Today, rain bands are passing through, but perhaps no rain will fall in my gauge. There may be several rainless days yet.

My gauge not valid for Manilla

Photo of dry wedge-type rain gauge

My rain gauge

The photo shows my personal rain gauge. It is dusty because it has been dry for the last 43 days.
Whether it rains in my gauge today or not, my reading cannot count in the record for the town of Manilla. It is as if it is this dry spell is not happening.
My gauge is very simple and not precise. It is hard to read to parts of a millimetre. I bought a cheap one, because there is no point in having a precise rain gauge in my yard. The yard is too sheltered to meet the Bureau of Meteorology standard. My house is also a kilometre away from the Post Office.

Manilla’s failed rainfall record

Rainfall was first recorded at the Manilla Post Office in March 1883. The record of readings was essentially unbroken through 132 years until the 26th of March 2015. There are towns with longer rainfall records, but not very many.
The last observer was the former Postmaster, Phil Pinch. When he left the district a year ago, no volunteer was found to  observe Manilla’s rainfall. For this failure, the people of Manilla should be deeply ashamed. We dropped the ball, in a game where our performance was recognised, not just locally but nationally.

Weather observations are vital

The climate is changing. We know this only because people, mainly volunteers, have kept careful accurate records decade after decade. The reason that there is so much uncertainty about the climate of the world is that long and reliable records, such as Manilla’s rainfall, are so very few.

A recent high-level paper on extreme weather events includes:

“Event attribution capabilities would be improved with better observational records, both near-real time and for historical context. Long homogeneous observed records are essential for placing events into a historical context and evaluating to what extent climate models reliably simulate the effect of decadal climate variability on extremes.”

Picking up the ball

This already year-long gap in the Manilla record will make it harder to use Manilla data in the future. However, if the record can be restarted before too long it will keep most of its value. “Get on with it, Manilla!”

[Note added 5 November 2017
The 38% failure rate of the automated rain gauge is reported in the post “Manilla’s automated rain gauge down again” of 5 November 2017.]


Photo of rain gauges

Manilla PO 055031

A 2007 photo of the official rain gauges at Manilla Post Office. It was received in a word.doc from the Bureau of Meteorology NSW Regional Observations Section on 2 April 2015, with advice on the selection of a replacement site.
The caption:
“Photo of both rain gauges at Manilla Post Office (taken 2007). The automatic flood warning gauge to the right. Both are embedded (dug in) to ground approximately 20 to 30cm deep.”

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2 thoughts on “No rain, and no rain gauge

  1. We got 9mm at Ambleside this afternoon. In this day, it seems remarkable that an automated station can not be installed, requiring no human interaction excepting occasional maintenance.

  2. Hi, Allan
    There is, in fact, an automated rain gauge associated with the former Manilla Post Office Station 055031. I have now added a photo to the post, showing the two gauges. This automated rain gauge is not a normal station. It is a Manilla River flood analysis station. It reports to the Bureau over a dedicated phone line.
    Data is published (available to the public) for only the last seven days on a Bureau of Meteorology web page called “NSW Daily Rainfall Bulletin – North West”:
    http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDN60172.html
    Manilla is listed under “Manilla River”, the fifth panel from the bottom of the page. (I guess it is under Manilla River rather than Namoi River because it is the nearest station to the centre of the Manilla River catchment.)

    The header says:
    “The data is provided for flood warning purposes and not all data will be available during non flood periods.”
    When the Post Office gauge was first abandoned, I consulted this web-page and found that current data was missing. The Bureau staff did not seem surprised as they use the data only if a flood is likely.
    I decided not to manually download from this web-page once each week, but use my own imperfect gauge.
    A Bureau technician moved the automatic gauge from the Post Office to a site that I suggested: a large locked yard in Alexander Lane behind the museum. The manual rain gauge is also stored there, I believe, but the site is not convenient for a volunteer to access.

    On that web-page you will note that the automatic rain gauge reading of 9.8 mm since 9 am on 18 March agrees quite well with your reading of 9 mm and my reading of 8.5 mm.

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