Numerous streams plunge from the high mountains toward the coast.  In places they rush through deep gorges between high mountains, again they pass peacefully through mountain valleys.  Everywhere they are fed by minor streams and waterfalls until at last, as they emerge into the broader valleys of the Abra and its tributaries, they are rivers of respectable size.

The great central valley of Abra is far from being a level plain.  In places, as about Manabo, Bukay, and Bangued, there are stretches of level land; but, for the most part, the country is rough and broken.  This valley is cut off from the sea by the Coast Range of mountains which forms the provincial line between Abra and Ilocos Sur, while another heavy spur forms the northern limits of Abra from Ilocos Sur to the Cordillera Central.  Two small and rather difficult passes afford entrance from the coastal plain into the valley, but the chief avenue of communication is the cut through which the Abra river reaches the sea.  So narrow is this entrance that, at high water, the river completely covers the floor and often raises its waters ten or fifteen feet up the canyon side.  In recent years a road has been cut in the rocks above the flood waters, but even to-day most of the traffic between Abra and the coast is carried on by means of rafts which are poled up the river. [7]

The rainfall averages about one hundred inches, and most of this precipitation takes place between May and the end of September.  This, coupled with the lack of forest, causes the rivers to become rushing torrents during the rainy season, while during the balance of the year most of them are mere rivulets.  Under these conditions there has been no development of navigation by the mountaineers.  On occasion they may construct a bamboo raft, but they possess no boats of any description.

The great fluctuation of the streams makes fishing an uncertain occupation; yet at least a dozen varieties of fish are known, and enough are taken to add materially to the food supply.

Deer and pig are fairly abundant, and a considerable number is killed each year; wild carabao roam the mountain sides and uninhabited valleys, but they are dangerous animals, and can seldom be taken with the primitive weapons of the natives.  Wild chickens are plentiful, and many are snared, together with smaller birds.  In fact, there is sufficient game and fish to support a considerable population, if the people would turn seriously to their capture, so that the oft repeated statement that the mountaineers of Abra were forced to agriculture is not entirely accurate.  It seems much more probable that, at the time of their entrance into the interior valleys, the Tinguian were already acquainted with terraced hillside fields, and that they developed them as needed.

The soil is fairly fertile, the rainfall abundant during the growing season, and the climate warm enough to insure good crops.  The thermometer ranges between 80 deg. and 85 deg. during the day, but there is generally a land or sea breeze, so that actual discomfort from the heat is unusual.  The nights are somewhat cooler, but a drop of a few degrees is felt so keenly that a person may be uncomfortarble at 70 deg..