## 4 Regional Scale Analysis
### Results  
The information on the worth exposed was then combined with the landslide hazard map in order to obtain the risk assessment of slope instability at regional level reported in Figure 7, through the process summarized in Section 3.2. Analysis of the results shown in Figure 7 demonstrates that about 42% of the territory is located in areas ranging from very low to moderate risk (1.6% very low, 12.3% low, 28.5% moderate). This means that most of the territory ranges include moderate-high risk (23.6%), high risk (16.7%), and finally very high risk (17.3%). In order to better describe the distribution of the risk associated with landslides due to glacier melting, two analyses were carried out: (i) the distribution of the risk at the municipality level and (ii) the distribution of the risk in different landscape units. The main aim of this phase was to provide a landslide risk map as support to local governments for identifying the priorities for the design of appropriate mitigation plans. At the municipality level, the computed risk index has been put in relation to Valle d'Aosta municipalities by averaging the values of the pixels that fall within the different town boundaries. In Figure 8, the risk distribution in the municipality in Valle d'Aosta was organized into box-plots. Comparing the results, we observe that the interquartile range box (called the IQR, which represents the middle 50% of the data) ranges between 75 (lowest value for Q1) in the low-risk class and 203 (highest value for Q3) in the high-risk class. The interquartile box for the whole region is between 105 and 162: this means that half of the territory was classified in this range, including risk values ranging from \"moderate\" to \"high\". Some municipalities that present the highest risk scores are, in order, Bionaz (570), Gressoney-La-Trinite (528), Courmayeur (494), Pre-Saint- Didier (493), Valtournenche (486), and Cogne (465). Figure 6: Aggregated worth exposed value in the Valle d’Aosta region. The map was created through GIS software, employing the data outlined in Table 2.  
One of the areas categorized as high risk is the Lys River Valley, which owes its name to the homonymous river, a left tributary of the Dora Baltea. Gressoney-La-Trinite, the second municipality with the highest risk score, is located in the upper part of the valley, at the foot of the Monte Rosa massif and near the Lys glacier. In particular, in the final stretch, we find a group of small villages on very steep slopes whose development has been strongly conditioned by avalanches and gravitational phenomena that have always characterized this valley in particular. This is the reason why this area is the subject of analysis at the local level in Section 5. The peculiarities of the Valle d'Aosta landscape and the territorial fragilities that characterize it make it necessary to correlate the areas at landslide risk with these threatened values. The aim of this analysis was to provide further information and tools aimed at protecting the regional territory and its landscapes, as well as support for planning choices concerning protection against the risks arising from possible gravitational movements and landslides that could occur in deglaciated areas. The Territorial Landscape Plan (Piano Territoriale Paesistico, PTP) of Valle d'Aosta was used for the identification of the different landscape units (Figure 9). Figure 7: Glacier melting related landslide risk map in Valle d’Aosta region. The map was created through GIS software, interpolating hazard and worth exposed maps (Figures 4 and 6). The landscape units defined by the PTP were related to the landslide risk map in order to have a first indication of the landscape types with the highest risk, through the averages calculated on the single units.