Sir John Monash, Personal Files Book 15, 1 April - 10 May 1917, Part 1

Second Army Intelligence.
April 1917
WEATHER OF APRIL, MAY and JUNE in the British Army Area,
based on observations attending over period from 10 to
20 years. From METEOROLOGICAL SECTION, R.E., G.H.Q
*****************************************************************************
APRIL and MAY are on the whole the months of best visibility,
least cloud and least rainfall; the haze of Summer has not begun
and the fogs of Autumn and Winter are past. The ground, however,
is not so dry as in the late Summer and early Autumn months, so
that the effect of the rain which falls is more marked than in
August or September.
Evaporation increases almost to its Summer value in APRIL,
so that, apart from water already in the ground, there is no more
to be got rid of by percolation than in the Summer months.
Temperature is, ho ever, variable, and a cold wet spell may occur
and be accompanied in APRIL by hail, sleet or snow; and in MAY
by hail or sleet, very rarely snow.
Thunderstorms are more frequent in MAY and JUNE than in any
other months of the year, and in MAY especially they bring hail.
JUNE is on the average wetter than APRIL or MAY, and it is often
one of the wettest months of the year. Nearly half the JUNES are
as wet or wetter than the three wettest APRILS of the last twenty
years. JUNE also is more cloudy usually than the Spring months
preceding it or the Summer months following it.
In the Southern part of the Britis Army area the amount of
rainfall steadily increases through MAY to quite high values in
JUNE but farther north MAY is sometimes wetter than JUNE.
Maps responded giving the distribution of average monthly
rainfall fo APRIL, MAY, JUNE. The lines separating areas
coloured differently are a approximate contours of rainfall lines
dividing areas of higher from areas of lower rainfall. The
average total rainfall for the month in inches is marked on each
area.
For example, places in the areas marked 1.8 have an average
rainfall var ing between 1.6 and 2.0 inches.
It will be seen that APRIL is the driest of the months
generally, and JUNE the wettest. The area of high rainfall to the
3.E. around MEZIERES, which is so marked in the Winter months, is
still a wet area; but the wet area of the Winter season N.W. from
EREVENT to BOULOGNE is less distinctly marked.
The average variation over the area of elements other than
rainfall is small. The days are usually 2 or 3 degrees warmer
South of ARRAS than further North, and frequently the nights are
colder; cloud is also slightly less in the South. A table is
appended which shows the average day and night temperatures of
the months under consideration, together with extreme values
which may occur. The values on the whole show a steady rise from
MARCH to JULY. The possibility of quite sharp frosts in APRIL
and the rarity of frosts in MAY is brought out clearly. The
lowest night temperatures of MAY and JUNE are not much above the
freezing point however
SPELLS of dry weather are rather mere frequent in JUNE than
in APRIL and MAY, but their average duration is rather less in
MAY and JUNE than in APRIL. On the average about one spell of a
week or more without rain occurs in each of the three months: and
about 2 spells of 3 days or more without rain. The number of
such spells at LILLE occurring in 27 years is shown here:
LILLE . . .
 

- 2 -
LILLE.
Spells of dry weather during 27 years.
 

______

APRIL.
FROSTS. The number of night frosts in April is very variable.
Thirteen occurred in 1892, none in 1896. The average number for
the month is two to three - less than a third of the frequency of
frosts in MARCH.
SNOW falls on the average about one day per month, and in
1903 it fell on as many as 6 days; it does not lie long on the
ground.
RAINFALL. On the average the month is the driest of the
year, the rainfall being between 1 and 2 inches. Rain falls on
about 2 days out of 5. Dry APRILS (with rainfall less than 1")
occur nearly one year in two, and very dry APRILS with rain less
than half an inch occur one year in seven. The three wettost
APRILS of the last 20 years have given together about 9 inches of
rain, and the three wettest JUNES gave about 15" of rain; eleven
JUNES were as wet or wetter than the three wettest APRILS.
APRIL is a dry month in respect of:
(a) its low average rainfall,
(b) the frequency c- very dry APRILS, and
c) the fact that the wettest APRILS are not excessively wet
months.
EVAPORITION. There is a considerable increase (40%) in the
rate of evaporation as compared with MARCH. This condition in
conjunction with the low rainfall, has a very marked and permanent
effect in the drying of the ground.
GALES average about three per month, or the odds are 10 to I
against a gale on any particular day.
THUNDERSTORMS are slightly More frequent than in MARCH: 10
in 20 years.

_______
MAY.
FROSTS do not occur in MAY on the average as often as one
night per month. There is a considerable increase in the average
night temperature - 45⁰ as compared with 39⁰ for APRIL; ground
frosts, occurring on clear nights after bright warm days, are not
infrequent.
SN0W is exceptional in May: at ARRAS it was reported twice
in about 30 years.
RAINFALL. For the southern part of the line MAY usually has
a rainfall intermediate between the low value of APRIL and the
high one of JUNE. In parts of the Second Army area, MAY is wetter
than APRIL or JUNE. Dry MAYS (less than an inch of rain) only
occur one year in five, and there has only been one MAY with a
rainfall less than half an inch in 20 years. Wet MAYS (over 3" 
of rain) occur about one year in three.
EVAPOPATION.  There is a further marked increase in this
respect as compared with APRIL, but as rainfall has increased too,
the amount that has to be drained away does not alter significantly.
GALES occur on an average one day in 20.
THUNDERSTORMS become more frequent; 48 in 20 years. This is
an important point: much of the rain of MAY will come in thunderstorms, 
i.e. it is heavy at the time and quickly over.
--------------

JUNE ... 

- 3 -
JUNE.
FROST & SNOW These are practically never experienced -
the night temperature averages 51⁰.
RAINFALL. JUNE is a very wet month, especially for the
southern part of the line. In only two years in the last 20 has
a rainfall less than an inch occurred, whereas this occurs in
almost half of the APRILS. The rainfall has been three inches or
more for about half of the JUNES of the period, and three years
gave rainfalls of the order 5 or 6". The number of rain days for
the month is not high (13), but the JUNE averages for rainfall
are brought up by the heavy downpours of thunderstorms, as MAY and
JUNE have higher thunderstorm frequency than any other months.
At ARRAS the average rainfalls for JUNE and APRIL are in the ratio
7:4 (2.3" as compared with 1.5")
EVAPORATION is approaching its maximum value in JUNE, but
rainfall is relatively high too, so that again the amount of water
to be eliminated by drainage is not significantly different from
that of APRIL and MAY.
GALES occur less than once per month (1 day in 43).
THUNDERSTORMS are about as frequent as in MAY; 45 in 20 years.
_____________
TABLES OF TEMPERTURE.

=============================

Diagram
CHART OF AVERAGE MONTHLY RAINFALL
(FROM METEOROLOGICAL SECTION, RE-COMPILED FROM RECORDS OF

20 YEARS)
SECOND ARMY INTELLIGENCE - APRIL 1917
 see original document

Diagram

DIAGRAM SHOWING RAINFALL 

DAY BY DAY AT HAZELBROUCK

AUGUST 1916 - MARCH 1917

SECOND ARMY INTELLEGENCY PORK 1917

Copy for G.O.C.

SECRET. 
THIRD AUSTRALIAN DIVISION.
Divisional Headquarters,
Ist. April, 1917.
[*HEADQUARTERS

No. G36/67

THIRD AUSTRALIAN DIVISION*]

G.O.C., 9th. Aust. Inf. Bde.
   "    "   11th Aust Inf Bde (For infmtn).
   "    "   3rd. Aust. Divl. Arty.        "
             "G" Staff.
             "Q"
              C.R.E.
1. With reference to Third Australian Division
Order No. 26, paras. 4 (a), (b), (c), the 9th. Brigade, during
the interval that will elapse before this Brigade proceeds to
QUELMES for training, in addition to forming the Divisional
Tactical Reserve, will be available for providing working parties
 in connection with the preparation for certain operations
which are in contemplation.
2. The Battalions will be allocated for work as
follows :
35^th (a). Battalion at OOSTHOVE FARM under direction of C.R.A.
34^th (b).         "         at NIEPPE.                                   ) Under direction of
36^th (c)         "          at PLOEGSTEERT WOOD        )         C.R.E.                                   
33^rd (d)        "          at ARMENTIERES under direction G.O.C. 11th.
                     Brigade.
 3. The 9th. Aust. M. G. Company and the 9th.
A.L.T.M. Battery will be at the disposal of the 9th. Brigade
for training, but the former will also be available to provide
a portion of the garrison of the ARMENTIERES Defences under
separate instructions to be issued.
4. Representatives of each of the four Battalions
will report to the respective authorities under whom they are to
work, not later than 4th. instant, in order to reconnoitre the
work to be done and to assist in the allocation of working parties 

and the preparation of working party tables for their respective 

units.
5. All personnel of these Infantry Battalions not
absorbed in working parties, will be available to 9th. Brigade
for training, and every possible advantage must be taken to carry
on systematic training.
6. 9th. Brigade will notify Divisional Headquarters,
as soon as possible, by wire, the proposed distribution of the
Battalions under para 2 above, but the Battalions which, at time
of relief, are Brigade Reserve should be allocated to OOSTHOVE
FARM and PLOEGSTEERT WOOD billets and duties.
7. In order to stimulate the personnel to their
best efforts, special steps are to be taken to explain to all
ranks that all work imposed upon them under the present orders
has been calculated for and will be directed towards driving the
enemy, this Spring and Summer, out of occupied territory.
E. H. Reynolds
Lieut-Colonel.
General Staff.
 

VERY SECRET.
THIRD AUSTRALLAN DIVISION.
Divisional Headquarters,
2nd. April, 1917.
Brigadier-General JOBSON.
Brigadier-General MCNICOLL, D.S.O.

                                                            ↨ [*See  Plan B dated 2.4.17*]          
1. Attached sheet of Tracing paper is marked with
co-ordinate lines to fit over squares 8, 9, 10, *c. of PLOEGSTEERT
Sheet, 28 S.W. 4, Scale 1:10,000 (Confidential Edition). -
2. It is proposed to assault and capture the enemy's
position as indicated by the following marks, (which must be regarded 
for the time being as purely tentative) viz. -
(a). The red line AA is th boundary between the 9th. Brigade.
on the right, and the l0th. Brigade on the left.
(b).The red line BB is the boundary between the 10th. Brigade,
and a New Zealand Brigade on its left.
(c). The green line CDE shows, approximately, the position on
which it is intended to finally dig in and consolidate
our forward position.

(d). The green line Dr shows, approximately, the position of
a rear line to be also consolidated.
(e). The green circles - marked "G" - show the approximate
positions for the establishment of a series of "outposts'
or "strong points", (themselves covered by a screen of
sentries in shell holes); these strong points to be consolidated 
and held, in order to break up counter-attacks
and to cover the consolidation of the line CDE.
3. The following assumptions may be made, namely that
Zero will be at dawn, that, after the capture of the enemy's front
and support lines - which must be completed by Zero plus 20
minutes - the artillery barrage will halt for 10 minutes on about
the line DF. There will then be a second "bound" for the capture
of the line of the ULSTER RESERVE trench - which must be completed
by Zero plus 45 minutes - the barrage then halting for 5 minutes
on about the line DE,- and then the barrage will creep beyond' the
line of the strong points G, finally coming to rest ^upon the line of
the UNCANNY trenches, and extending to the South so as to envelop
our new right flank. - This latter standing barrage will be maintained 
for three days. - Mines will be blown at Zero at or near
the points marked by red dots, numbered H. - There will be no
Tanks. - Assume that all wire disclosed by the air photos will
have been effectively cut by Zero hour, and the whole of the objectives
P.T.0.
 

(2).
heavily bombarded for four days prior to Zero.-
4. On above data, please make a careful study of the
map, the contours and the aeroplane photos and draw up, in outline, 
a plan of your dispositions for the action. Prepare a
preliminary report and submit same as soon as possible, but not
later than April 9th. - Your preliminary report should make
definite proposals on the following points. -
(1). Dispositions of the Brigade as a whole, naming Units.
(2). Internal dispositions of the Battalions.
(3). Allotment of tasks to Battalions.
(4). Distribution of Lewis Guns during consolidation.
(5). Employment of Vickers Guns before and during assault
and consolidation.
(6). Question of holding Brigade or Battalion reserves,
in our lines. (There will be a whole Brigade in
Divisional Reserve at HYDE PARK CORNER).
(7). Proposed strengths and organization of carrying parties.
(8). Arrangements for prompt supply of entrenching tools,
wire and ammunition to advanced lines and posts.
(9). Methods of assembly, issuing from our trenches, and
deployment.
(10). Question of keeping direction during the advance.
(11). Problem of crossing the LA DOUVE (Left Brigade only).
5. It must be fully understood that while Brigadiers
will be permitted as free a hand as possible in the execution of
the tasks allotted to Brigades, the final plans will have to conform 
to the general requirements and conditions imposed by the
plans of Corps and Division.-
6. Address reply to me personally.
Major-General.-
Commanding 3rd. Australian Division.
 

Extract from G 26/410

4 April 17

                                    ______________
 

SECRET.
-----------
AUSTRALIAN IMPERIAL FORCE.
---------
Headquarters
9th Australian Infantry Brigade.
6th April, 1917.

Major-General Monash, C.B., V.D.
G.O.C.
Third Australian Division.
(1) The preliminary report asked for in your letter
of 2nd instant is enclosed herewith.
(2) The considerations which led to the plan suggested 
have not been stated in this report as it was thought
they would be better set down in a separate memorandum.
(3) Two main plans suggested themselves.
(4) Plan "A":
Attack line C.J. with two Battalions
Right Battalion from C to D
Left Battalion from D to J
Third Battalion to move on line D.H.
Fourth Battalion to supply carrying parties
and the Brigade Reserve.
(5) The arguments for this plan were:
(a) The Right flank C.D. being the Right of
the Divisional front must be made secure
against possible counter-attacks from the
trench system South-East of that line.
(b) A reasonably strong force seemed necessary
for this purpose.
(c) It seemed probable that the trench system
South-West of the line D.J. would be, so
badly damaged by our Artillery, that one
Battalion would suffice to capture them.
(d) One complete Battalion would be free for
carrying parties and the Brigade Reserve.
(6) The arguments against it were:
(a) The weakness of the Right flank is more
apparent than real. The flank would be
well protected by our Artillery, and by
the Brigade on our Right. The country
would not lend itself to large counter
attacks and with the assistance available
a smaller force than a Battalion would
probably suffice to cope with the small
counter-attacks likely to be made.
(b) It is possible our Artillery would not
demolish all the enemy's deep dug-outs in
his front line. Machine Guns emerging
from such dug-outs would probably cause
heavy losses unless an adequate force were
available to deal with them quickly. The
task of so doing might be too much for one
Battalion attacking along the whole front
even though a second Battalion were supporting it.
∅

1.