The current drought now has a severe rainfall shortage of 240 months duration that must have commenced in 1999.

[For explanation of this graph, see below: “About drought duration graphs”.]

[These graphs have been updated to October 2019, showing much worse shortages.]

Shortages at 2018

Shortages of rainfall became alarming in 2018. The winter months had extreme shortages of 2-month to 6-month duration. Earlier and later dry months contributed to longer-term extreme shortages from 9 months up to 30-months.
In months since November 2018 none of the short-term rainfall totals for durations from two months to six months has been even a severe shortage. In other respects, the drought has deepened. Because recent monthly rainfall values have seldom risen above normal, periods of severe or extreme shortage have become longer and longer. As at May 2019, extreme shortages prevail at 15-, 18-, 24-, 30-, 72- and 84-month durations.
Severe shortages have developed at even longer durations, at 96-, 120-, 150- and 240-months. As is clear from the graph, the 240-month severe shortage incorporates the 2002 drought into the 2018 drought. This was not evident until now.
As shown, the severe shortages of 150- and 240-month duration, current in April 2019, did not persist in observations for May. They could resume if later months do not have much rain. [Actually, this was a copy-down error.]

Compete record updated to May

When the graph of the complete record of months of rainfall shortage at Manilla is updated to May 2019 it is obvious that the current drought is one of the great droughts in history.
Although this drought seemed to have a sudden onset, shortages of longer duration actually began earlier: the longer the duration concerned, the earlier its time of onset.. The 2018 pattern is like the droughts of 1902, 1940 and 1946. Droughts that actually had a sudden onset were those of 1912, 1957 and 1965.

About drought duration graphs

These graphs show the onset, persistence, and breaking of episodes of extreme and severe rainfall shortage (droughts) at Manilla. The first shows detail since 2000. The second shows the complete historical record from 1884. The graph features and the data analysis are explained in the post “Rainfall Shortage History: Manilla”.

Extreme shortages, up to the 1st percentile, are shown in red and severe shortages, up to the 5th percentile, are shown in grey.
The dashed line labelled “Last Good Data” is a limitation of observed cumulative rainfall deficiency. Future observations may make any point to the right of this line more extreme.

The current drought now has an extreme rainfall shortage of 84 months duration that must have commenced in 2012.

A new graph

This graph shows the onset, persistence, and breaking of episodes of extreme and severe rainfall shortage (droughts) at Manilla since 2000. It is a part of a graph of the complete historical record from 1884. In this case, the time axis is expanded to resolve individual months.

The features of this “onset-to-breaking” kind of graph and the data analysis are explained in the post “Rainfall Shortage History: Manilla”.

Extreme shortages, up to the 1st percentile, are shown in red and severe shortages, up to the 5th percentile, are shown in grey.
The dashed line labelled “Last Good Data” is a limitation to determining cumulative rainfall deficiency. Future observations may make any point to the right of this line more extreme.

The pattern of rainfall shortages from 2000

Shortages before 2018

In 2000 there were no rainfall shortages classed as “severe”. There had been hardly any since 1994.
The drought that occurred in winter 2002 had extreme rainfall shortages at all durations from 3 months to 12 months. Severe shortages extended even further: from 2 months to 30 months. However this was a much shorter drought than six others in the history of Manilla.

Although severe rainfall shortages (grey) occurred at intervals between 2002 and 2018, they formed small clusters, mainly at short durations. Years affected were 2005, 2008, 2009, 2012, 2013, 2014, and 2017. By 2014, there was public concern about shortage of rainfall. Although there were few seasonal severe shortages at that time, the graph shows that there were severe shortages at durations from 12 months to 30 months through 2013 and 2014.

With the benefit of current data, we can see that severe and even extreme shortages of duration longer than 60 months were, in fact, initiated in 2012 or earlier. They were not apparent at the time, however. In October 2016, in a post “Is There Any Drought Now?”, I argued that there was no evidence of drought at that time.

An alternative expression of rainfall status during this time is a graph of smoothed rainfall anomalies in the post “17 Years of “Droughts and Flooding Rains” at Manilla”.

Shortages at 2018

Shortages of rainfall became alarming in 2018. The winter months had extreme shortages of 2-month to 6-month duration. Earlier and later dry months contributed to a 15-month extreme shortage, such as had not occurred since 1966, half a century earlier.
After November 2018 none of the short-term rainfall totals for durations less than nine months has been even a severe shortage. In other respects, the drought has deepened. As recent monthly rainfall values have scarcely risen above normal, durations of severe or extreme shortage have become longer and longer. As at March 2019, extreme shortages prevail at 30 months, 72 months and 84 months. Severe shortages prevail at even longer durations, now up to 120 months (10 years).

Other Current Graphs

Other graphs of the drought, current to March 2019 data, are in two posts: “March Rain Leaves Drought Extreme”, and “Rainfall Shortage Sequence 03/2019”.

Notes

The Millennium Drought absent
“Rainfall Shortages” or “Droughts”?
Short droughts are worst

The Millennium Drought absent

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